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

Bumps [@salesforce/cli-plugins-testkit](https://github.com/salesforcecli/cli-plugins-testkit) from 5.1.7 to 5.1.8.
- [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@5.1.7...5.1.8)

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

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -17,7 +17,7 @@
   },
   "devDependencies": {
     "@oclif/plugin-command-snapshot": "^5.0.6",
-    "@salesforce/cli-plugins-testkit": "^5.1.3",
+    "@salesforce/cli-plugins-testkit": "^5.1.8",
     "@salesforce/dev-scripts": "^8.3.0",
     "@salesforce/plugin-command-reference": "^3.0.59",
     "@salesforce/plugin-source": "^2.11.4",

yarn.lock

@@ -1636,12 +1636,12 @@
     istanbul-reports "^3.1.6"
     jsforce "^2.0.0-beta.29"
 
-"@salesforce/cli-plugins-testkit@^5.1.3", "@salesforce/cli-plugins-testkit@^5.1.7":
-  version "5.1.7"
-  resolved "https://registry.yarnpkg.com/@salesforce/cli-plugins-testkit/-/cli-plugins-testkit-5.1.7.tgz#79c21424fa7775c9b3220ee566cf4a467154478e"
-  integrity sha512-ZItoRNujnYN5andRLsTjVXp82W114d9TceWEbOOB2CrUofFdqiSbyiKxfg2/VkB2zk1t3B/ueVkFbiQtoLowPA==
+"@salesforce/cli-plugins-testkit@^5.1.7", "@salesforce/cli-plugins-testkit@^5.1.8":
+  version "5.1.8"
+  resolved "https://registry.yarnpkg.com/@salesforce/cli-plugins-testkit/-/cli-plugins-testkit-5.1.8.tgz#789630cc389c13fe016c7593aa4ac8bbf532e3bd"
+  integrity sha512-3/jvEc+RVWFRbGPtyEzNJ5eb84p7HuLYDZ1EAokLVgDpnW5qy9UpBWrU0Tv98MaQhfRtPdSc/gmzB6m6nqWZLg==
   dependencies:
-    "@salesforce/core" "^6.4.7"
+    "@salesforce/core" "^6.5.1"
     "@salesforce/kit" "^3.0.15"
     "@salesforce/ts-types" "^2.0.9"
     "@types/shelljs" "^0.8.15"