minor #49001 Speed up Psalm tests (danepowell)

This PR was submitted for the 6.3 branch but it was squashed and merged into the 5.4 branch instead.

Discussion
----------

Speed up Psalm tests

| Q             | A
| ------------- | ---
| Branch?       | 6.3
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->
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The setupphp maintainer [recommends caching the couchbase extension](shivammathur/setup-php#593 (comment)) using the [cache-extensions action](https://github.com/shivammathur/cache-extensions). This should speed up Psalm runs from 14 minutes to 2 minutes!

Commits
-------

89be707 Speed up Psalm tests

.github/workflows/psalm.yml

@@ -19,12 +19,30 @@ jobs:
     name: Psalm
     runs-on: Ubuntu-20.04
 
+    env:
+      php-version: '8.1'
+      extensions: json,couchbase,memcached,mongodb,redis,xsl,ldap,dom
     steps:
+      - name: Setup cache environment
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: ${{ env.php-version }}
+          extensions: ${{ env.extensions }}
+          key: cache-v1 # can be any string, change to clear the extension cache.
+
+      - name: Cache extensions
+        uses: actions/cache@v3
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '8.1'
-          extensions: "json,couchbase,memcached,mongodb,redis,xsl,ldap,dom"
+          php-version: ${{ env.php-version }}
+          extensions: ${{ env.extensions }}
           ini-values: "memory_limit=-1"
           coverage: none