Bump CI regarding MSRV

Author: faern

.github/workflows/rust.yml

@@ -117,7 +117,7 @@ jobs:
         with:
           profile: minimal
           # when updating this, also update rust-version in Cargo.toml
-          toolchain: 1.31.0
+          toolchain: 1.63.0
           override: true
       - run: cargo build
       - run: cargo build --features reopen-1,reopen-03,meta-logging-in-format,syslog-3
@@ -134,7 +134,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: 1.48.0
+          toolchain: 1.63.0
           override: true
       - run: cargo build --features date-based
   msrv_syslog_4:
@@ -150,7 +150,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: 1.51.0
+          toolchain: 1.63.0
           override: true
       - run: cargo build --features syslog-4
   msrv_syslog_6:
@@ -166,7 +166,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: 1.59.0
+          toolchain: 1.63.0
           override: true
       - run: cargo build --features syslog-6
   fmt_and_clippy: