Make the message when not pruning more helpful

The original message made it sound like it checked the store and decided there was nothing to prune, in reality pruning just did not run if run_install was not set.

src/pnpm-store-prune/index.ts

@@ -5,7 +5,7 @@ import { patchPnpmEnv } from '../utils'
 
 export function pruneStore(inputs: Inputs) {
   if (inputs.runInstall.length === 0) {
-    console.log('Pruning is unnecessary.')
+    console.log('No install commands were run, skipping pnpm store prune, remember to run it after pnpm install if caching the store.')
     return
   }