fix bitbucket build failures

packages/netlify-cms-backend-bitbucket/babel.config.js

@@ -1,3 +0,0 @@
-const config = require('../../babel.config.js');
-
-module.exports = config;

packages/netlify-cms-backend-bitbucket/webpack.config.js

@@ -1 +1,3 @@
-module.exports = require('../../webpack.config.js');
+const { getConfig } = require('../../scripts/webpack.js');
+
+module.exports = getConfig();