[redwood] Fix file permissions and add support for build script (#4999)

Some files require execution privileges, such as Prisma, so we must preserve the file mode.

We also want redwood to behave the same as other frameworks and use `yarn build` if available.

test/lib/deployment/now-deploy.js

@@ -3,6 +3,7 @@ const { createHash } = require('crypto');
 const path = require('path');
 const _fetch = require('node-fetch');
 const fetch = require('./fetch-retry.js');
+const fileModeSymbol = Symbol('fileMode');
 const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
 
 async function nowDeploy(bodies, randomness, uploadNowJson) {
@@ -14,7 +15,9 @@ async function nowDeploy(bodies, randomness, uploadNowJson) {
       sha: digestOfFile(bodies[n]),
       size: bodies[n].length,
       file: n,
-      mode: path.extname(n) === '.sh' ? 0o100755 : 0o100644,
+      mode:
+        bodies[n][fileModeSymbol] ||
+        (path.extname(n) === '.sh' ? 0o100755 : 0o100644),
     }));
 
   const { FORCE_BUILD_IN_REGION, NOW_DEBUG, VERCEL_DEBUG } = process.env;
@@ -80,9 +83,7 @@ async function nowDeploy(bodies, randomness, uploadNowJson) {
 }
 
 function digestOfFile(body) {
-  return createHash('sha1')
-    .update(body)
-    .digest('hex');
+  return createHash('sha1').update(body).digest('hex');
 }
 
 async function filePost(body, digest) {
@@ -247,4 +248,5 @@ module.exports = {
   fetchWithAuth,
   nowDeploy,
   fetchTokenWithRetry,
+  fileModeSymbol,
 };