add caching of test data in gh workflow (#36)

.github/workflows/test_and_deploy.yml

@@ -37,7 +37,13 @@ jobs:
           python-version: "3.10"
 
     steps:
-      # Run tests
+      - name: Cache Test Data
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/.movement/*
+          key: cached-test-data
+          enableCrossOsArchive: true
       - uses: neuroinformatics-unit/actions/test@v2
         with:
           python-version: ${{ matrix.python-version }}