bootstrap: Use gcc 7.3.0 from microchip

Author: wavexx

utils/bootstrap.py

@@ -47,9 +47,9 @@
     'avr-gcc': {
         'version': '7.3.0',
         'url': {
-            'Linux': 'http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-x86_64-pc-linux-gnu.tar.bz2',
-            'Windows': 'http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-i686-w64-mingw32.zip',
-            'Darwin': 'http://downloads.arduino.cc/tools/avr-gcc-7.3.0-atmel3.6.1-arduino7-x86_64-apple-darwin14.tar.bz2',
+            'Linux': 'https://ww1.microchip.com/downloads/aemDocuments/documents/DEV/ProductDocuments/SoftwareTools/avr8-gnu-toolchain-3.7.0.1796-linux.any.x86_64.tar.gz',
+            'Windows': 'https://ww1.microchip.com/downloads/aemDocuments/documents/DEV/ProductDocuments/SoftwareTools/avr8-gnu-toolchain-3.7.0.1796-win32.any.x86_64.zip',
+            'Darwin': 'https://ww1.microchip.com/downloads/aemDocuments/documents/DEV/ProductDocuments/SoftwareTools/avr8-gnu-toolchain-osx-3.7.0.518-darwin.any.x86_64.tar.gz',
         },
     },
     'prusa3dboards': {