Replace self-hosted runners with Ubicloud (#5885)

Motivation:

The self-hosted runners installed on AWS can't scale out automatically
and the price of EC2 is more expensive than [Ubicloud
runners](https://www.ubicloud.com/docs/about/pricing#github-actions)

Additionally, the official self-hosted runners do not support the Docker
environment so Ubicloud runners are safer and less vulnerable.

Modifications:

- Fixed Actions workflow files to use `ubicloud-standard-8` which is
almost the same spec with EC2 instances.

Result:

- Better CI environments.

.github/workflows/actions_build.yml

@@ -25,47 +25,32 @@ env:
   DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
 
 jobs:
-  choose-self-hosted:
-    runs-on: ubuntu-latest
-    outputs:
-      runner: ${{ steps.runner.outputs.runner }}
-
-    steps:
-      - id: runner
-        run: |
-          if [[ "${{ github.event_name }}" == "pull_request" ]]; then
-            echo "runner=self-hosted-unsafe" >> "$GITHUB_OUTPUT"
-          else
-            echo "runner=self-hosted-safe" >> "$GITHUB_OUTPUT"
-          fi
-
   build:
-    needs: [ choose-self-hosted ]
     if: github.repository == 'line/armeria'
     runs-on: ${{ matrix.on }}
     timeout-minutes: 120
     strategy:
       fail-fast: false
       matrix:
-        on: [ "${{ needs.choose-self-hosted.outputs.runner }}", macos-12, windows-latest ]
+        on: [ ubicloud-standard-8, macos-12, windows-latest ]
         java: [ 21 ]
         include:
           - java: 8
-            on: ${{ needs.choose-self-hosted.outputs.runner }}
+            on: ubicloud-standard-8
           - java: 11
-            on: ${{ needs.choose-self-hosted.outputs.runner }}
+            on: ubicloud-standard-8
           - java: 17
-            on: ${{ needs.choose-self-hosted.outputs.runner }}
+            on: ubicloud-standard-8
             leak: true
           - java: 17
-            on: ${{ needs.choose-self-hosted.outputs.runner }}
+            on: ubicloud-standard-8
             min-java: 11
           - java: 17
-            on: ${{ needs.choose-self-hosted.outputs.runner }}
+            on: ubicloud-standard-8
             min-java: 17
             coverage: true
           - java: 21
-            on: ${{ needs.choose-self-hosted.outputs.runner }}
+            on: ubicloud-standard-8
             snapshot: true
             # blockhound makes the build run about 10 minutes slower
             blockhound: true
@@ -111,7 +96,7 @@ jobs:
       - name: Build with Gradle (Shading only)
         run: |
           ./gradlew --no-daemon --stacktrace shadedJar shadedTestJar trimShadedJar \
-          ${{ startsWith(matrix.on, 'self-hosted') && '--max-workers=8' || '--max-workers=2' }} --parallel \
+          ${{ startsWith(matrix.on, 'ubicloud') && '--max-workers=8' || '--max-workers=2' }} --parallel \
           ${{ matrix.coverage && '-Pcoverage' || '' }} \
           -PnoLint \
           -PbuildJdkVersion=${{ env.BUILD_JDK_VERSION }} \
@@ -130,7 +115,7 @@ jobs:
       - name: Build with Gradle
         run: |
           ./gradlew --no-daemon --stacktrace build \
-          ${{ startsWith(matrix.on, 'self-hosted') && '--max-workers=8' || '--max-workers=2' }} --parallel \
+          ${{ startsWith(matrix.on, 'ubicloud') && '--max-workers=8' || '--max-workers=2' }} --parallel \
           ${{ matrix.coverage && '-Pcoverage' || '' }} \
           ${{ matrix.leak && '-Pleak' || '' }} \
           ${{ matrix.blockhound && '-Pblockhound' || '' }} \
@@ -255,8 +240,6 @@ jobs:
 
   site:
     if: github.repository == 'line/armeria'
-    # ubuntu-latest is preferred for site job.
-    # node_modules need complicated dependencies that are difficult to install on self-hosted runners.
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:

.github/workflows/publish-release.yml

@@ -13,7 +13,7 @@ jobs:
   publish:
     name: Publish final artifacts
     if: github.repository == 'line/armeria'
-    runs-on: self-hosted-safe
+    runs-on: ubicloud-standard-8
     steps:
       - uses: actions/checkout@v4