Update ghcr.io/cloudnative-pg/postgresql Docker tag to v18

.gitea/workflows/lint-test.yaml

@@ -5,7 +5,7 @@ on:
 
 jobs:
   lint-test:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.gitea/workflows/release-charts-cloudflared.yml

@@ -14,7 +14,7 @@ env:
 
 jobs:
   release:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.gitea/workflows/release-charts-generic-device-plugin.yml

@@ -14,7 +14,7 @@ env:
 
 jobs:
   release:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.gitea/workflows/release-charts-gitea-actions.yml

@@ -14,7 +14,7 @@ env:
 
 jobs:
   release:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.gitea/workflows/release-charts-postgres-cluster.yml

@@ -14,7 +14,7 @@ env:
 
 jobs:
   release:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.gitea/workflows/renovate.yaml

@@ -12,7 +12,7 @@ on:
 
 jobs:
   renovate:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     container: ghcr.io/renovatebot/renovate:41
     steps:
       - name: Checkout