modified to use proxy input

src/context.js

@@ -7,6 +7,7 @@ function getRequiredVars() {
     githubToken: core.getInput('token'),
     staticSiteGenerator: core.getInput('static_site_generator'),
     generatorConfigFile: core.getInput('generator_config_file'),
+    proxy: core.getInput('proxy'),
     enablement: core.getInput('enablement') === 'true'
   }
 }