ci: use more jobs

Configure to use four parallel jobs.

Apparently github has been providing hosted runners with 4 CPUs since January,
2024 [0].

The MacOS runner may only provide 3 CPUs [1], but four jobs on three CPUs
shouldn't be harmful and may actually help test performance, so we treat all
target platforms uniformly.

[0]: https://github.blog/news-insights/product-news/github-hosted-runners-double-the-power-for-open-source/
[1]: https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
           sudo apt-get install quilt gnupg2 libio-pty-perl
       - name: Test
         env:
-          STG_PROVE_OPTS: "--jobs=2"
+          STG_PROVE_OPTS: "--jobs=4"
           STG_TEST_OPTS: "--verbose-log"
           STG_PROFILE: "release"
         run: |
@@ -45,17 +45,17 @@ jobs:
           sudo apt-get install asciidoc asciidoctor docbook-xsl-ns xmlto
       - name: Build Docs Asciidoc
         run: |
-          make -j2 doc
+          make -j4 doc
       - name: Build Docs Asciidoctor
         env:
           USE_ASCIIDOCTOR: "1"
         run: |
-          make -j2 doc
+          make -j4 doc
       - name: Install HTML Docs
         env:
           USE_ASCIIDOCTOR: "1"
         run: |
-          make -j2 htmldir="$GITHUB_WORKSPACE"/stgit-html install-html
+          make -j4 htmldir="$GITHUB_WORKSPACE"/stgit-html install-html
       - name: Upload HTML Docs
         uses: actions/upload-artifact@v4
         with:
@@ -140,7 +140,7 @@ jobs:
           sudo cpanm IO::Pty
       - name: Test
         env:
-          STG_PROVE_OPTS: "--jobs=2"
+          STG_PROVE_OPTS: "--jobs=4"
           STG_TEST_OPTS: "--verbose-log"
           STG_PROFILE: ${{ matrix.profile }}
         run: |
@@ -235,7 +235,7 @@ jobs:
       - name: Pre-test Check 2
         shell: msys2 {0}
         env:
-          STG_PROVE_OPTS: "--jobs=2"
+          STG_PROVE_OPTS: "--jobs=4"
           STG_TEST_OPTS: "--verbose-log"
           STG_PROFILE: "release"
         run: |
@@ -247,7 +247,7 @@ jobs:
           STG_TEST_OPTS: "--verbose-log"
           STG_PROFILE: "release"
         run: |
-          timeout 900s make -C t SHELL_PATH=C:/msys64/usr/bin/bash --jobs=3 test
+          timeout 900s make -C t SHELL_PATH=C:/msys64/usr/bin/bash --jobs=4 test
       - name: Show Failures
         if: ${{ failure() }}
         shell: msys2 {0}