Merge pull request #1785 from davidhewitt/pin-bitflags

ci: pin bitflags for MSRV job

.github/workflows/ci.yml

@@ -137,6 +137,7 @@ jobs:
         run: |
           cargo update -p indexmap --precise 1.6.2
           cargo update -p hashbrown:0.11.2 --precise 0.9.1
+          cargo update -p bitflags --precise 1.2.1
 
       - name: Build docs
         run: cargo doc --no-deps --no-default-features --features "${{ steps.settings.outputs.all_additive_features }}"