fix: getInputFromEnv could return empty string

Author: exuanbo

dist/index.js

@@ -1,3 +1,5 @@
+/* eslint-disable @typescript-eslint/strict-boolean-expressions */
+
 // https://github.com/actions/toolkit/blob/27f76dfe1afb2b7e5e679cd8e97192d34d8320e6/packages/core/src/core.ts#L128
 function getInputFromEnv(name: string, options: { required: true }): string
 function getInputFromEnv(
@@ -10,10 +12,10 @@ function getInputFromEnv(
 ): string | undefined {
   const value = process.env[`INPUT_${name.replace(/ /g, '_').toUpperCase()}`]
   const { required = false } = options
-  if (required && value === undefined) {
+  if (required && !value) {
     throw new Error(`Input required and not supplied: ${name}`)
   }
-  return value?.trim()
+  return !value ? undefined : value.trim()
 }
 
 type Input = Readonly<{