ci(build): Test build using defined MSRV (currently 1.60)

Author: KokaKiwi

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         platform: [ubuntu-latest, windows-latest, macos-latest]
-        toolchain: [stable, beta, nightly]
+        toolchain: ['1.60', stable, beta, nightly]
     runs-on: ${{ matrix.platform }}
 
     steps: