build: reduce git noise #3812

Problem:
The generateServiceClient task is noisy in CI logs:

    > ts-node ./scripts/build/generateServiceClient.ts
    ...
    Updating files:  66% (2895/4337)
    Updating files:  67% (2906/4337)
    Updating files:  68% (2950/4337)
    Updating files:  69% (2993/4337)
    Updating files:  70% (3036/4337)
    ...
    You are in 'detached HEAD' state. You can look around, make experimental
    changes and commit them, and you can discard any commits you make in this
    state without impacting any branches by switching back to a branch.
    ...

Solution:
- Use the `--quiet` option.
- Pass `advice.detachedHead=false` config option when doing `git checkout`.

Author: justinmk3

scripts/build/generateServiceClient.ts

@@ -56,9 +56,20 @@ async function cloneJsSdk(dir: string): Promise<void> {
             ? // Local repo exists already: just update it and checkout the tag.
               // Fetch only the tag we need.
               //      git fetch origin tag v2.950.0 --no-tags
-              ['-C', dir, 'fetch', 'origin', 'tag', tag, '--no-tags']
+              ['-C', dir, 'fetch', '--quiet', 'origin', 'tag', tag, '--no-tags']
             : // Local repo does not exist: clone it.
-              ['clone', '-b', tag, '--depth', '1', 'https://github.com/aws/aws-sdk-js.git', dir]
+              [
+                  '-c',
+                  'advice.detachedHead=false',
+                  'clone',
+                  '--quiet',
+                  '-b',
+                  tag,
+                  '--depth',
+                  '1',
+                  'https://github.com/aws/aws-sdk-js.git',
+                  dir,
+              ]
 
         const gitCmd = child_process.execFile('git', gitArgs, { encoding: 'utf8' })
 
@@ -69,7 +80,15 @@ async function cloneJsSdk(dir: string): Promise<void> {
             gitCmd.stdout?.removeAllListeners()
 
             // Only needed for the "update" case, but harmless for "clone".
-            const gitCheckout = child_process.spawnSync('git', ['-C', dir, 'checkout', '--force', tag])
+            const gitCheckout = child_process.spawnSync('git', [
+                '-c',
+                'advice.detachedHead=false',
+                '-C',
+                dir,
+                'checkout',
+                '--force',
+                tag,
+            ])
             if (gitCheckout.status !== undefined && gitCheckout.status !== 0) {
                 console.log(`error: git: status=${gitCheckout.status} output=${gitCheckout.output.toString()}`)
             }