Wait until spring-boot.rb is available when updating Homebrew tap

Closes gh-41561

.github/actions/await-http-resource/action.yml

@@ -0,0 +1,20 @@
+name: Await HTTP Resource
+description: Waits for an HTTP resource to be available (a HEAD request succeeds)
+inputs:
+  url:
+    description: 'The URL of the resource to await'
+    required: true
+runs:
+  using: composite
+  steps:
+    - name: Await HTTP resource
+      shell: bash
+      run: |
+        url=${{ inputs.url }}
+        echo "Waiting for $url"
+        until curl --fail --head --silent ${{ inputs.url }} > /dev/null
+        do
+          echo "."
+          sleep 60
+        done
+        echo "$url is available"

.github/actions/sync-to-maven-central/action.yml

@@ -38,13 +38,6 @@ runs:
         release: true
         generate-checksums: true
     - name: Await
-      shell: bash
-      run: |
-        url=${{ format('https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot/{0}/spring-boot-{0}.jar', inputs.spring-boot-version) }}
-        echo "Waiting for $url"
-        until curl --fail --head --silent $url > /dev/null
-        do
-          echo "."
-          sleep 60
-        done
-        echo "$url is available"
+      uses: ./.github/actions/await-http-resource
+      with:
+        url: ${{ format('https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot/{0}/spring-boot-{0}.jar', inputs.spring-boot-version) }}

.github/actions/update-homebrew-tap/action.yml

@@ -16,6 +16,10 @@ runs:
         path: updated-homebrew-tap-repo
         repository: spring-io/homebrew-tap
         token: ${{ inputs.token }}
+    - name: Await Formula
+      uses: ./.github/actions/await-http-resource
+      with:
+        url: https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot-cli/${{ inputs.spring-boot-version }}/spring-boot-cli-${{ inputs.spring-boot-version }}-homebrew.rb
     - name: Update Homebrew Tap
       shell: bash
       run: |