ci: fix for cargo-msrv needing at least 1.59 now (#850)

Author: tomtau

.github/workflows/ci.yml

@@ -79,7 +79,7 @@ jobs:
         with:
           kind: msrv
           tools: cargo-msrv
-          toolchain: 1.57.0
+          toolchain: 1.59.0
       - name: Check msrv
         shell: sh
         run: for crate in "derive" "generator" "grammars" "meta" "pest" "vm"; do cd "$crate" && cargo msrv verify && cd ..; done
@@ -160,4 +160,4 @@ jobs:
           tools: cargo-semver-checks
       - name: check semver compatibility
         shell: bash
-        run: ./semvercheck.sh
+        run: ./semvercheck.sh