Change pnpm formatting to match pnpm native style (#14)

Currently, every time pnpm writes the lock file, it uses single quotes, but prettier is currently configured for double quotes. This PR changes the configuration so that for the pnpm lock file, prettier uses single quotes so that it and pnpm are no longer fighting over formatting. lol.

.prettierrc

@@ -1,5 +1,13 @@
 {
   "singleQuote": false,
   "arrowParens": "always",
-  "trailingComma": "all"
+  "trailingComma": "all",
+  "overrides": [
+    {
+      "files": "pnpm-lock.yaml",
+      "options": {
+        "singleQuote": true
+      }
+    }
+  ]
 }