fix(core): unpin all dependencies, closes #6944 (#6966)

.github/workflows/test-core.yml

@@ -82,5 +82,13 @@ jobs:
           workspaces: core -> ../target
           save-if: ${{ matrix.features.key == 'all' }}
 
+      - name: Downgrade crates with MSRV conflict
+        # The --precise flag can only be used once per invocation.
+        run: |
+          cargo update -p time --precise 0.3.15
+          cargo update -p ignore --precise 0.4.18
+          cargo update -p winnow --precise 0.4.1
+          cargo update -p raw-window-handle --precise 0.5.0
+
       - name: test
         run: cargo test --target ${{ matrix.platform.target }} ${{ matrix.features.args }}