fix: correct Sparkle signature for v0.1.2

The script ran twice causing a signature mismatch between appcast.xml and GitHub.
Updated signature to match the actual ZIP file on GitHub.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Prot10

appcast.xml

@@ -18,7 +18,7 @@
                     <li>- Removed version badge from Home header</li>
                 </ul>
             ]]></description>
-            <enclosure url="https://github.com/Prot10/MyMacCleaner/releases/download/v0.1.2/MyMacCleaner-v0.1.2.zip" sparkle:edSignature="zmekczg/gBS/V7CN9uohqAIiUuwQFDJDv+7wEg7rli7RrJK1LmHH4WxiDtIRI6PRptsl7JCNNNfxLLHbGX+2Dg==" length="4451205" type="application/octet-stream"/>
+            <enclosure url="https://github.com/Prot10/MyMacCleaner/releases/download/v0.1.2/MyMacCleaner-v0.1.2.zip" sparkle:edSignature="ecDIzafMWJNy0BrvRQIcOrj0Ka71MMPUDQyfPPUcLbRnzDpVin/NDcXku2tphSa1bRkfHiOOeF1aZu83cClRDQ==" length="4468640" type="application/octet-stream"/>
         </item>