ci: explicitly install subversion

SVN is required both for WP test setup and deployment actions, but no
longer present on default "ubuntu-latest" environments. Add a step to
install it.

.github/workflows/test.yml

@@ -19,6 +19,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Install SVN
+        run: |
+          if ! command -v svn > /dev/null; then
+            sudo apt-get update
+            sudo apt-get install -y subversion
+          fi
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:

.github/workflows/wordpress-plugin-asset-update.yml

@@ -10,6 +10,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Install SVN
+        run: |
+          if ! command -v svn > /dev/null; then
+            sudo apt-get update
+            sudo apt-get install -y subversion
+          fi
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:

.github/workflows/wordpress-plugin-deploy.yml

@@ -11,6 +11,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Install SVN
+        run: |
+          if ! command -v svn > /dev/null; then
+            sudo apt-get update
+            sudo apt-get install -y subversion
+          fi
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with: