chore: downgrade to Rust 1.68 (#19411)

Problems still persist from https://github.com/denoland/deno/pull/19407
-- downgrading to try out 1.68

.github/workflows/ci.generate.ts

@@ -5,7 +5,7 @@ import * as yaml from "https://deno.land/std@0.173.0/encoding/yaml.ts";
 // Bump this number when you want to purge the cache.
 // Note: the tools/release/01_bump_crate_versions.ts script will update this version
 // automatically via regex, so ensure that this line maintains this format.
-const cacheVersion = 35;
+const cacheVersion = 36;
 
 const Runners = (() => {
   const ubuntuRunner = "ubuntu-22.04";

.github/workflows/ci.yml

@@ -293,7 +293,7 @@ jobs:
             ~/.cargo/registry/index
             ~/.cargo/registry/cache
             ~/.cargo/git/db
-          key: '35-cargo-home-${{ matrix.os }}-${{ hashFiles(''Cargo.lock'') }}'
+          key: '36-cargo-home-${{ matrix.os }}-${{ hashFiles(''Cargo.lock'') }}'
         if: '!(github.event_name == ''pull_request'' && matrix.skip_pr)'
       - name: Restore cache build output (PR)
         uses: actions/cache/restore@v3
@@ -305,7 +305,7 @@ jobs:
             !./target/*/*.zip
             !./target/*/*.tar.gz
           key: never_saved
-          restore-keys: '35-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-${{ matrix.job }}-'
+          restore-keys: '36-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-${{ matrix.job }}-'
       - name: Apply and update mtime cache
         if: '!(github.event_name == ''pull_request'' && matrix.skip_pr) && (!startsWith(github.ref, ''refs/tags/''))'
         uses: ./.github/mtime_cache
@@ -592,7 +592,7 @@ jobs:
             !./target/*/gn_out
             !./target/*/*.zip
             !./target/*/*.tar.gz
-          key: '35-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-${{ matrix.job }}-${{ github.sha }}'
+          key: '36-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-${{ matrix.job }}-${{ github.sha }}'
   publish-canary:
     name: publish canary
     runs-on: ubuntu-22.04

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.69.0"
+channel = "1.68.0"
 components = ["rustfmt", "clippy"]