Fixed broken DFU uploader for stm32f103 targets

Issue #855

Author: valeros

platform.json

@@ -307,6 +307,7 @@
       "version": "~0.7.0"
     },
     "tool-stm32duino": {
+      "type": "uploader",
       "optional": true,
       "owner": "platformio",
       "version": "~1.0.1"

platform.py

@@ -76,9 +76,11 @@ def configure_default_packages(self, variables, targets):
             if board.startswith(("portenta", "opta", "nicla", "giga")):
                 dfu_package = "tool-dfuutil-arduino"
                 self.packages.pop("tool-dfuutil")
+                self.packages.pop("tool-stm32duino")
             elif build_mcu.startswith("stm32f103"):
                 dfu_package = "tool-stm32duino"
             else:
+                self.packages.pop("tool-stm32duino")
                 self.packages.pop("tool-dfuutil-arduino")
             self.packages[dfu_package]["optional"] = False