ci: migrate runs-on to Twilio runner labels + SHA-pin actions

Author: charlottestjohn

.github/workflows/delete-old-branches.yml

@@ -7,12 +7,12 @@ on:
 jobs:
   delete-old-branches:
     name: Delete old branches
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-latest-large
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5  # v2
       - name: Run delete-old-branches-action
-        uses: beatlabs/delete-old-branches-action@v0.0.10
+        uses: beatlabs/delete-old-branches-action@6e94df089372a619c01ae2c2f666bf474f890911  # v0.0.10
         with:
           repo_token: ${{ github.token }}
           date: '7 days ago'

.github/workflows/maven.yml

@@ -10,7 +10,7 @@ on:
 jobs:
   publish:
     name: Publish to Maven Central
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-latest-large
     permissions:
       contents: read
 
@@ -21,10 +21,10 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd  # v5
 
       - name: Set up Java & Maven for Central
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@c1e323688fd81a25caa38c78aa6df2d33d3e20d9  # v4
         with:
           distribution: 'temurin'
           java-version: '8'