Update test MSRV to match the actually-supported minimum Rust version. (#100)

Author: obi1kenobi

.github/workflows/test-action.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest', 'windows-latest', 'macos-latest']
-        toolchain: ["1.84", "stable", "beta"]
+        toolchain: ['1.85', 'stable', 'beta']
         experimental: [false]
         include:
           - os: 'ubuntu-latest'