allow saving cache to be optional (#131)

config.js

@@ -5,6 +5,7 @@ const core = require('@actions/core')
 const github = require('@actions/github')
 
 const bazeliskVersion = core.getInput('bazelisk-version')
+const cacheSave = core.getBooleanInput('cache-save')
 const cacheVersion = core.getInput('cache-version')
 const moduleRoot = core.getInput('module-root')
 
@@ -137,6 +138,7 @@ core.exportVariable('BAZELISK_GITHUB_TOKEN', token)
 
 module.exports = {
   baseCacheKey,
+  cacheSave,
   bazeliskCache: {
     enabled: core.getBooleanInput('bazelisk-cache'),
     files: [`${moduleRoot}/.bazelversion`],