add --if-exists flag to migrate command

this is to prevent the action from exiting with error when there are no migrations
generated from the current migration, which is a perfectly valid case

dist/index.js

@@ -41798,7 +41798,7 @@ function migrate(keepMigrationsFile) {
             env: Object.assign(Object.assign({}, process.env), { npm_config_yes: String(true) })
         });
         yield (0, exec_1.exec)('npm install');
-        yield (0, exec_1.exec)('npx nx migrate --run-migrations=migrations.json --create-commits', [], {
+        yield (0, exec_1.exec)('npx nx migrate --run-migrations=migrations.json  --if-exists --create-commits', [], {
             env: Object.assign(Object.assign({}, process.env), { npm_config_yes: String(true), NX_MIGRATE_SKIP_INSTALL: String(true) })
         });
         // sometimes migrations change packages without installing them, so naivly install dependencies here again

src/nx-migrate.ts

@@ -10,7 +10,7 @@ export async function migrate(keepMigrationsFile: boolean): Promise<void> {
   })
   await exec('npm install')
   await exec(
-    'npx nx migrate --run-migrations=migrations.json --create-commits',
+    'npx nx migrate --run-migrations=migrations.json  --if-exists --create-commits',
     [],
     {
       env: {