Start relying on Rust 1.39.0

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.37.0
+          toolchain: 1.39.0
           override: true
 
       # cargo fmt does not build the code, and running it in a fresh clone of
@@ -41,7 +41,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.37.0
+          toolchain: 1.39.0
           override: true
       - name: cargo fetch
         uses: actions-rs/cargo@v1
@@ -71,7 +71,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.37.0
+          toolchain: 1.39.0
           override: true
       - name: Install cargo-tarpaulin
         uses: actions-rs/cargo@v1

rust-toolchain

@@ -0,0 +1 @@
+1.39.0