Fix CI (downgrade a dependency for MSRV build)

.github/workflows/ci.yml

@@ -108,6 +108,22 @@ jobs:
       - name: Cache Dependencies
         uses: Swatinem/rust-cache@v2
 
+      # Generally MSRV dump is not considered a breaking change in by the Rust community.
+      # Thus a minor or a patch version dump of a dependency of ours, can bump MSRV.
+      # (remember that `cargo` uses newest semver compatible versions by default)
+      #
+      # It's silly to bump MSRV every time minor dependency update does (note that this update can
+      # happen even after our crate is published; so users may need to downgrade crates in
+      # `Cargo.lock` independently of how we test our crates), so we downgrade their versions in
+      # MSRV CI specifically instead. This allows as to
+      # 1. Not update MSRV unless we really need to
+      # 2. Test newest (or at least newer) versions of crates in CI
+      - name: Downgrade deps for MSRV
+        if: ${{ matrix.rust == 'msrv' }}
+        run: |
+            cargo update -p atomic-write-file@0.1.3 --precise 0.1.2
+        
+
       # NB. Don't test (build) examples so we can use non-msrv features in them (--tests/--doc)
       - name: Compile
         run: |