Update Wasmtime's MSRV to 1.79.0 (#9202)

This is coupled with today's release of Rust 1.81.0 and the policy of
updating our MSRV when that comes out.

.github/actions/install-rust/action.yml

@@ -23,7 +23,7 @@ runs:
         elif [ "${{ inputs.toolchain }}" = "msrv" ]; then
           echo "version=1.$msrv.0" >> "$GITHUB_OUTPUT"
         elif [ "${{ inputs.toolchain }}" = "wasmtime-ci-pinned-nightly" ]; then
-          echo "version=nightly-2024-09-03" >> "$GITHUB_OUTPUT"
+          echo "version=nightly-2024-09-05" >> "$GITHUB_OUTPUT"
         else
           echo "version=${{ inputs.toolchain }}" >> "$GITHUB_OUTPUT"
         fi

Cargo.toml

@@ -161,7 +161,7 @@ authors = ["The Wasmtime Project Developers"]
 edition = "2021"
 # Wasmtime's current policy is that this number can be no larger than the
 # current stable release of Rust minus 2.
-rust-version = "1.78.0"
+rust-version = "1.79.0"
 
 [workspace.lints.rust]
 # Turn on some lints which are otherwise allow-by-default in rustc.