fix bossac ver

Author: NanoCodeBug

board/package_pawpet_index.json

@@ -34,7 +34,7 @@
             {
               "packager": "arduino",
               "name": "bossac",
-              "version": "1.9.1-arduino2"
+              "version": "1.8.0-48-gb176eee"
             },
             {
               "packager": "arduino",