[StepSecurity] ci: Harden GitHub Actions (#488)

Signed-off-by: StepSecurity Bot <bot@stepsecurity.io>

.github/workflows/code-coverage-test.yml

@@ -5,6 +5,9 @@ on:
     branches:
       - main
 
+permissions:
+  contents: read
+
 jobs:
   build:
     name: coverage-test
@@ -13,7 +16,7 @@ jobs:
 
     steps:
       - name: Clone postgres repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           repository: 'postgres/postgres'
           ref: 'REL_15_STABLE'
@@ -80,7 +83,7 @@ jobs:
           pg_ctl -D /opt/pgsql/data -l logfile start
 
       - name: Clone pg_stat_monitor repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           path: 'src/pg_stat_monitor'
 
@@ -110,7 +113,7 @@ jobs:
         working-directory: src/pg_stat_monitor
 
       - name: Upload
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@b9fd7d16f6d7d1b5d2bec1a2887e65ceed900238 # v4.6.0
         with:
           verbose: true
           token: ${{ secrets.CODECOV_TOKEN }}
@@ -127,7 +130,7 @@ jobs:
 
       - name: Upload logs on fail
         if: ${{ failure() }}
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
         with:
           name: Regressions diff and postgresql log
           path: |