Bump MSRV to 1.64.0

Author: dlon

.github/workflows/ci.yml

@@ -63,7 +63,7 @@ jobs:
       matrix:
         # MSRV. Not considered breaking when this has to be bumped.
         # But should be mentioned in the changelog.
-        rust: [stable, beta, nightly, 1.56.0]
+        rust: [stable, beta, nightly, 1.64.0]
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v2

CHANGELOG.md

@@ -22,6 +22,8 @@ Line wrap the file at 100 chars.                                              Th
 
 
 ## [Unreleased]
+### Changed
+- Bump minimum supported Rust version (MSRV) to 1.64.0.
 
 
 ## [0.5.1] - 2023-05-15