feat: add option to save resulting pr information into json

src/bin/release-please.ts

@@ -16,6 +16,7 @@
 
 import {coerceOption} from '../util/coerce-option';
 import * as yargs from 'yargs';
+import {writeFile} from 'fs';
 import {GitHub, GH_API_URL, GH_GRAPHQL_URL} from '../github';
 import {Manifest, ManifestOptions, ROOT_PROJECT_PATH} from '../manifest';
 import {ChangelogSection, buildChangelogSections} from '../changelog-notes';
@@ -396,7 +397,10 @@ function manifestOptions(yargs: yargs.Argv): yargs.Argv {
       default: 'release-please-config.json',
       describe: 'where can the config file be found in the project?',
     })
-    .option('manifest-file', {
+    .option('json', {
+      default: null,
+      describe: 'save json output to a file',
+    })    .option('manifest-file', {
       default: '.release-please-manifest.json',
       describe: 'where can the manifest file be found in the project?',
     });
@@ -533,6 +537,13 @@ const createReleasePullRequestCommand: yargs.CommandModule<
       }
     } else {
       const pullRequestNumbers = await manifest.createPullRequests();
+      if (argv.json){
+        writeFile(argv.json.toString(), JSON.stringify(pullRequestNumbers, null, 2), (err) => {
+          if (err) {
+            console.error("Error writing file:", err);
+          }
+        });
+      }
       console.log(pullRequestNumbers);
     }
   },