chore(dev-deps): bump @salesforce/cli-plugins-testkit

Bumps [@salesforce/cli-plugins-testkit](https://github.com/salesforcecli/cli-plugins-testkit) from 5.0.5 to 5.1.2.
- [Release notes](https://github.com/salesforcecli/cli-plugins-testkit/releases)
- [Changelog](https://github.com/salesforcecli/cli-plugins-testkit/blob/main/CHANGELOG.md)
- [Commits](salesforcecli/cli-plugins-testkit@5.0.5...5.1.2)

---
updated-dependencies:
- dependency-name: "@salesforce/cli-plugins-testkit"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

yarn.lock

@@ -909,11 +909,11 @@
   integrity sha512-+1VkjdD0QBLPodGrJUeqarH8VAIvQODIbwh9XpP5Syisf7YoQgsJKPNFoqqLQlu+VQ/tVSshMR6loPMn8U+dPg==
 
 "@salesforce/cli-plugins-testkit@^5":
-  version "5.0.5"
-  resolved "https://registry.yarnpkg.com/@salesforce/cli-plugins-testkit/-/cli-plugins-testkit-5.0.5.tgz#54a4ec57a10b10b3e3040cfb754972666a3ec100"
-  integrity sha512-TketFUfimWg7T0LJGaXtfelvp6Zy3i2sYwuULSBYiyPceqUTZJXPXNzbHC987b6E3OcT4K6mIxLiVbF//kzvMQ==
+  version "5.1.2"
+  resolved "https://registry.yarnpkg.com/@salesforce/cli-plugins-testkit/-/cli-plugins-testkit-5.1.2.tgz#a8d0c988d26d22cbaa4f19e6be9f0d1a28238ef2"
+  integrity sha512-3tF1invyikFvkDfnRdFJBrhDV4gcO0cf7gKRT/9GmIHOF88qjiPiKy4VYx7q1fZI8xn6ZEov0LmMziLUVYjdtg==
   dependencies:
-    "@salesforce/core" "^6.2.0"
+    "@salesforce/core" "^6.4.1"
     "@salesforce/kit" "^3.0.15"
     "@salesforce/ts-types" "^2.0.9"
     "@types/shelljs" "^0.8.15"
@@ -947,7 +947,7 @@
     semver "^7.5.4"
     ts-retry-promise "^0.7.1"
 
-"@salesforce/core@^6.2.0", "@salesforce/core@^6.4.0", "@salesforce/core@^6.4.1":
+"@salesforce/core@^6.4.0", "@salesforce/core@^6.4.1":
   version "6.4.2"
   resolved "https://registry.yarnpkg.com/@salesforce/core/-/core-6.4.2.tgz#e6e5e2d5e6ad17f1cbe0feb5a0e55e8b74c91e3c"
   integrity sha512-ZtLwgI18f1th6SY0fKmuiyVGGwTXPy4nI+KfXzkww/vqdPxDhAfoHwqvFeo4tjFE2rldK7IPiIIYdtpsaI8d5g==