Update MSRV to 1.57

jturner314 · jturner314 · commit 1ca1e9a76679 · 2021-12-07T01:22:02.000-05:00
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -21,7 +21,7 @@ jobs:
           - stable
           - beta
           - nightly
-          - 1.51.0  # MSRV
+          - 1.57.0  # MSRV
 
     steps:
       - uses: actions/checkout@v2
diff --git a/Cargo.toml b/Cargo.toml
@@ -3,6 +3,7 @@
 name = "ndarray"
 version = "0.15.4"
 edition = "2018"
+rust-version = "1.57"
 authors = [
   "Ulrik Sverdrup \"bluss\"",
   "Jim Turner"
