refactor: add yarn to dev/buld scripts, update postinstall

run `yarn` automatically on `yarn dev` or `yarn build` to 1- update dependencies if needed, 2- trigger the `postinstall` script which will now remove the git-contributor-cache.json file to start the environment fresh each time

Author: wackerow

package.json

@@ -3,10 +3,10 @@
   "version": "8.5.2",
   "private": true,
   "scripts": {
-    "dev": "yarn clean-commit-history && next dev",
-    "postinstall": "yarn theme",
-    "build": "yarn clean-commit-history && next build",
-    "clean-commit-history": "touch ./src/data/git-contributor-cache.json && rm ./src/data/git-contributor-cache.json",
+    "dev": "yarn && next dev",
+    "postinstall": "yarn theme && yarn rm-contributor-cache",
+    "build": "yarn && next build",
+    "rm-contributor-cache": "touch ./src/data/git-contributor-cache.json && rm ./src/data/git-contributor-cache.json",
     "postbuild": "next-sitemap",
     "start": "next start",
     "lint": "next lint",