CI: Cache archives downloaded by apt (#8159)

Belt-and-braces in case GitHub apt mirrors start acting up again: On any
successful apt install, cache the deb files downloaded/needed for the
step, so on next run the mirrors need not be consulted. (That is: trade
apt mirror access with GitHub cache access, which is more reliable)

.github/workflows/coverage.yml

@@ -116,8 +116,9 @@ jobs:
           ls -lsha
 
       - name: Install dependencies
-        working-directory: repo
-        run: ./ci/ci-install.bash coverage
+        uses: ./repo/.github/actions/install-deps
+        with:
+          stage: coverage
 
       - name: Download code coverage data
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8

.github/workflows/format.yml

@@ -27,7 +27,9 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Install packages for build
-        run: ./ci/ci-install.bash format
+        uses: ./repo/.github/actions/install-deps
+        with:
+          stage: format
 
       - name: Configure git identity
         run: |

.github/workflows/reusable-build.yml

@@ -90,7 +90,9 @@ jobs:
             ${{ env.CACHE_KEY }}
 
       - name: Install packages for build
-        run: ./ci/ci-install.bash build
+        uses: ./repo/.github/actions/install-deps
+        with:
+          stage: build
 
       - name: Build
         run: |

.github/workflows/reusable-lint-py.yml

@@ -24,7 +24,9 @@ jobs:
           path: repo
 
       - name: Install dependencies
-        run: ./ci/ci-install.bash lint-py
+        uses: ./repo/.github/actions/install-deps
+        with:
+          stage: lint-py
 
       - name: Configure
         run: |

.github/workflows/reusable-rtlmeter-run.yml

@@ -66,11 +66,14 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           path: repo
-          sparse-checkout: ci
+          sparse-checkout: |
+            .github/actions
+            ci
 
       - name: Install dependencies
-        working-directory: repo
-        run: ./ci/ci-install.bash rtlmeter-run
+        uses: ./repo/.github/actions/install-deps
+        with:
+          stage: rtlmeter-run
 
       - name: Checkout RTLMeter
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7

.github/workflows/reusable-test.yml

@@ -85,8 +85,9 @@ jobs:
           key: ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.suite }}
 
       - name: Install test dependencies
-        run: |
-          ./ci/ci-install.bash test
+        uses: ./repo/.github/actions/install-deps
+        with:
+          stage: test
 
       - name: Set up Python venv
         uses: ./repo/.github/actions/setup-venv