ci: simplify the Coverity script a bit

Also, address https://github.com/systemd/systemd/pull/24252#issuecomment-1208747320
by using a pre-defined e-mail address stored in the GH Action secrets.

.github/workflows/coverity.yml

@@ -17,27 +17,14 @@ jobs:
     runs-on: ubuntu-22.04
     if: github.repository == 'systemd/systemd'
     env:
-      COVERITY_SCAN_BRANCH_PATTERN:     "${{ github.ref}}"
-      COVERITY_SCAN_NOTIFICATION_EMAIL: ""
-      COVERITY_SCAN_PROJECT_NAME:       "${{ github.repository }}"
-      # Set in repo settings -> secrets -> repository secrets
+      # Set in repo settings -> secrets -> actions
       COVERITY_SCAN_TOKEN:              "${{ secrets.COVERITY_SCAN_TOKEN }}"
-      CURRENT_REF:                      "${{ github.ref }}"
+      COVERITY_SCAN_NOTIFICATION_EMAIL: "${{ secrets.COVERITY_SCAN_NOTIFICATION_EMAIL }}"
     steps:
       - name: Repository checkout
         uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      # https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#setting-an-environment-variable
-      - name: Set the $COVERITY_SCAN_NOTIFICATION_EMAIL env variable
-        run: echo "COVERITY_SCAN_NOTIFICATION_EMAIL=$(git log -1 ${{ github.sha }} --pretty=\"%aE\")" >> "$GITHUB_ENV"
-      - name: Install Coverity tools
-        run: tools/get-coverity.sh
       # Reuse the setup phase of the unit test script to avoid code duplication
       - name: Install build dependencies
         run: sudo -E .github/workflows/unit_tests.sh SETUP
-      # Preconfigure with meson to prevent Coverity from capturing meson metadata
-      - name: Preconfigure the build directory
-        run: meson cov-build -Dman=false
-      - name: Build
-        run: tools/coverity.sh build
-      - name: Upload the results
-        run: tools/coverity.sh upload
+      - name: Build & upload the results
+        run: tools/coverity.sh