GitHub Actions CI workflow.

Ok, *THIS* one is lot more effort than other Workflows, as we have to
recompile mod_perl to ensure that it matches the version of Perl that we
are building/testnig with.

Worse yet, that _also_ requires that we build our own copy of Apache, as
the stock Ubuntu version has threads enabled (and all of our Perls are
non-threaded).

But wait, there's more!  Perls prior to 5.20 were not compiled as
shrplib out of the box, so we can't use those for testing here (unless
we want to recompile Perl as well).

Even more frustrating... Apache will refuse to start as `root`, so we
have to create our own `github` User to run the tests as, and have to
remember to `sudo --user github` when we want to do that.

Author: bleargh45

.github/workflows/perl-ci.yml

@@ -0,0 +1,164 @@
+---
+name: CI
+
+on: [push]
+
+env:
+  APACHE_RELEASE: http://archive.apache.org/dist/httpd/httpd-2.4.46.tar.gz
+  MODPERL_RELEASE: http://www.cpan.org/authors/id/S/SH/SHAY/mod_perl-2.0.11.tar.gz
+
+jobs:
+  build:
+    name: "Build a distribution tarball"
+    runs-on: ubuntu-latest
+
+    container:
+      image: perldocker/perl-tester:latest
+
+    steps:
+      - name: Setup GitHub user
+        run: |
+          apt-get update
+          apt-get install -y sudo
+          adduser --uid 1001 github
+
+      - name: Build Apache
+        run: |
+          apt-get install -y libapr1 libapr1-dev libaprutil1 libaprutil1-dev
+          wget --no-verbose $APACHE_RELEASE
+          tar -xzf httpd-*.tar.gz
+          cd httpd*/
+            ./configure --bindir=/usr/local/bin/ --with-mpm=prefork
+            make -j 4
+            make install
+          cd ../
+          rm -rf httpd-*
+
+      - name: Build mod_perl
+        run: |
+          wget --no-verbose $MODPERL_RELEASE
+          tar -xzf mod_perl-*.tar.gz
+          cd mod_perl*/
+            perl Makefile.PL MP_NO_THREADS=1
+            make -j 4
+            make install
+          cd ../
+          rm -rf mod_perl*
+
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Install CPM + Dist::Zilla Author Bundle
+        uses: perl-actions/install-with-cpm@stable
+        with:
+          sudo: false
+          install: |
+            Dist::Zilla::PluginBundle::Author::GTERMARS
+            Dist::Zilla::PluginBundle::ApacheTest
+
+      - name: Install dependencies
+        run: cpm install -g --no-test --show-build-log-on-failure $(dzil listdeps --author --missing)
+
+      - name: Test
+        run: |
+          chown -R github .
+          sudo --user github dzil test --all --test-verbose
+
+      - name: Build tarball
+        run: dzil build
+
+      - name: Upload tarball artifact
+        uses: actions/upload-artifact@v2
+        with:
+          name: tarball
+          path: "*.gz"
+
+      - name: Archive CPM logs
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@v2
+        with:
+          name: build.log
+          path: ~/.perl-cpm/build.log*
+
+  test:
+    name: "Perl v${{ matrix.perl-version }}"
+    needs: build
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        perl-version:
+          - "latest"
+          - "5.30"
+          - "5.28"
+          - "5.26"
+          - "5.24"
+          - "5.22"
+          - "5.20"
+
+    container:
+      image: perl:${{ matrix.perl-version }}
+
+    steps:
+      - name: Setup GitHub user
+        run: |
+          apt-get update
+          apt-get install -y sudo
+          adduser --uid 1001 github
+
+      - name: Build Apache
+        run: |
+          apt-get install -y libapr1 libapr1-dev libaprutil1 libaprutil1-dev
+          wget --no-verbose $APACHE_RELEASE
+          tar -xzf httpd-*.tar.gz
+          cd httpd*/
+            ./configure --bindir=/usr/local/bin/ --with-mpm=prefork
+            make -j 4
+            make install
+          cd ../
+          rm -rf httpd-*
+
+      - name: Build mod_perl
+        run: |
+          wget --no-verbose $MODPERL_RELEASE
+          tar -xzf mod_perl-*.tar.gz
+          cd mod_perl*/
+            perl Makefile.PL MP_NO_THREADS=1
+            make -j 4
+            make install
+          cd ../
+          rm -rf mod_perl*
+
+      - name: Download tarball artifact
+        uses: actions/download-artifact@v2
+        with:
+          name: tarball
+
+      - name: Unpack tarball
+        run: tar -xz --strip-components 1 -f *.gz
+
+      - name: Perl version
+        run: perl -V
+
+      - name: Install dependencies
+        uses: perl-actions/install-with-cpanm@v1
+        with:
+          sudo: false
+          args: "--installdeps . --with-recommends"
+
+      - name: Build
+        run: |
+          perl Makefile.PL
+          make
+
+      - name: Test
+        run: |
+          chown -R github .
+          sudo --user github make test TEST_VERBOSE=1
+
+      - name: Archive CPANM logs
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@v2
+        with:
+          name: build.log
+          path: ~/.cpanm/work/*/build.log