Add GHA dependabot config, bump codecov action (#3459)

.github/dependabot.yaml

@@ -6,4 +6,8 @@ updates:
       interval: weekly
     labels:
       - "dependencies"
-      - "go"
+      - "go"
+  - package-ecosystem: "github-actions"
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/dendrite.yml

@@ -262,7 +262,7 @@ jobs:
           POSTGRES_PASSWORD: postgres
           POSTGRES_DB: dendrite
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           flags: unittests
           fail_ci_if_error: true

.github/workflows/schedules.yaml

@@ -110,7 +110,7 @@ jobs:
           grep -Ev 'relayapi|setup/mscs|api_trace' sytest.cov > final.cov
           go tool covdata func -i="$(find Sytest* -name 'covmeta*' -type f -exec dirname {} \; | uniq | paste -s -d ',' -)"
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           files: ./final.cov
           flags: sytest
@@ -234,7 +234,7 @@ jobs:
           grep -Ev 'relayapi|setup/mscs|api_trace' complement.cov > final.cov
           go tool covdata func -i="$(find Complement* -name 'covmeta*' -type f -exec dirname {} \; | uniq | paste -s -d ',' -)"
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           files: ./final.cov
           flags: complement