Revert "experiment with sccache"

This reverts commit 8ef51dc122.

.github/workflows/build_test.yml

@@ -8,10 +8,6 @@ on:
     branches:
       - main
 
-env:
-  SCCACHE_GHA_ENABLED: true
-  RUSTC_WRAPPER: sccache
-
 jobs:
   build_all:
     name: Rust project - latest
@@ -34,18 +30,14 @@ jobs:
           # avoid the default "-D warnings" which thrashes cache
           rustflags: ""
 
-      - name: Run sccache-cache
-        uses: mozilla-actions/sccache-action@v0.0.3
-
-
       # https://github.com/actions/cache/blob/main/examples.md#rust---cargo
       - uses: actions/cache@v3
         with:
           path: |
             ~/.cargo/bin/
-#            ~/.cargo/registry/index/
-#            ~/.cargo/registry/cache/
-#            ~/.cargo/git/db/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
             target/
           key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}