Added cache for vscode used for e2e tests (#498)

* added caching of VS Code also for lint

Even if linting doesn't require the vscode part of the cache, we are not separating the two cases so that we only have one cache to maintain, and linting being a faster task (and a task that should fail less than tests) will update the cache more often, speeding up the run of the tests afterwards

.github/workflows/ci.yml

@@ -20,13 +20,14 @@ jobs:
         uses: actions/setup-node@v1
         with:
           node-version: '12'
-      - name: Restore Dependencies
+      - name: Restore Dependencies and VS Code test instance
         uses: actions/cache@v2
         with:
           path: |
             node_modules
             */*/node_modules
-          key: ${{ runner.os }}-${{ hashFiles('**/yarn.lock') }}
+            packages/foam-vscode/.vscode-test
+          key: ${{ runner.os }}-${{ hashFiles('**/yarn.lock') }}-${{ hashFiles('packages/foam-vscode/src/test/run-tests.ts') }}
       - name: Install Dependencies
         run: yarn
       - name: Check Lint Rules
@@ -47,13 +48,14 @@ jobs:
         uses: actions/setup-node@v1
         with:
           node-version: '12'
-      - name: Restore Dependencies
+      - name: Restore Dependencies and VS Code test instance
         uses: actions/cache@v2
         with:
           path: |
             node_modules
             */*/node_modules
-          key: ${{ runner.os }}-${{ hashFiles('**/yarn.lock') }}
+            packages/foam-vscode/.vscode-test
+          key: ${{ runner.os }}-${{ hashFiles('**/yarn.lock') }}-${{ hashFiles('packages/foam-vscode/src/test/run-tests.ts') }}
       - name: Install Dependencies
         run: yarn
       - name: Build Packages