fix(exportfunctions): process.env.FUNCTION_NAME is now called K_SERVICE

Firebase has changed the environment variable where the name of the currently invoked function is
stored. This commit adresses that change.

fix #7

Author: george43g

src/default.ts

@@ -56,7 +56,7 @@ export default function (__dirname: string, __filename: string, exports: any, di
     const relPath = absPath.substr(absFuncDir.length + 1); /* ? */
     const funcName = funcNameFromRelPath(relPath); /* ? */
     const propPath = funcName.replace(/-/g, '.'); /* ? */
-    if (!process.env.FUNCTION_NAME || process.env.FUNCTION_NAME === funcName) {
+    if (!process.env.K_SERVICE || process.env.K_SERVICE === funcName) {
       // eslint-disable-next-line import/no-dynamic-require, global-require, no-eval
       const module = eval('require')(resolve(__dirname, funcDir, relPath));
       if (!module.default) continue;

src/export-functions.ts

@@ -130,7 +130,7 @@ const disabledLogger = {
   },
 };
 
-const getFunctionInstance = () => process.env.FUNCTION_NAME;
+const getFunctionInstance = () => process.env.K_SERVICE;
 const isDeployment = () => !getFunctionInstance();
 const funcNameMatchesInstance = (funcName: string) => funcName === getFunctionInstance();
 const getTriggerFromModule = (inputModule: any) => inputModule?.default;