fix: respect signoff in config (#2247)

Signed-off-by: Mateusz Urbanek <mateusz.urbanek.98@gmail.com>

Author: shanduur

src/manifest.ts

@@ -121,6 +121,7 @@ export interface ReleaserConfig {
   releaseLabels?: string[];
   extraLabels?: string[];
   initialVersion?: string;
+  signoff?: string;
 
   // Changelog options
   changelogSections?: ChangelogSection[];
@@ -160,6 +161,7 @@ interface ReleaserConfigJson {
   'changelog-sections'?: ChangelogSection[];
   'release-as'?: string;
   'skip-github-release'?: boolean;
+  signoff?: string;
   draft?: boolean;
   prerelease?: boolean;
   'draft-pull-request'?: boolean;
@@ -1358,6 +1360,7 @@ function extractReleaserConfig(
     skipSnapshot: config['skip-snapshot'],
     initialVersion: config['initial-version'],
     excludePaths: config['exclude-paths'],
+    signoff: config['signoff'],
   };
 }