Update maven.yml

Cache pip dependencies?

.github/workflows/maven.yml

@@ -22,6 +22,13 @@ jobs:
         java-version: '17'
         distribution: 'temurin'
         cache: maven
+    - name: Cache pip dependencies
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-
     - name: Fail on whitespace errors
       run: git show HEAD --check
     - name: Install global requirements