Remove CI check for Rust 1.29

In preparation for starting to merge patches that rely on an MSRV of
1.41 update the CI pipeline.

.github/workflows/rust.yml

@@ -25,10 +25,9 @@ jobs:
               AS_DEPENDENCY: true
               DO_NO_STD: true
               DO_DOCS: true
-          - rust: 1.29.0
+          - rust: 1.41.1
             env:
               AS_DEPENDENCY: true
-              PIN_VERSIONS: true
     steps:
       - name: Checkout Crate
         uses: actions/checkout@v2