build: bump version to 0.1.2 and apply production release signature

Author: aoaim

pubspec.yaml

@@ -1,7 +1,7 @@
 name: pubmed_mobile
 description: "A mobile PubMed literature search client."
 publish_to: 'none'
-version: 0.1.1
+version: 0.1.2+1
 
 environment:
   sdk: ^3.11.0