Added support for MegaCore boards

.github/workflows/main.yml

@@ -32,6 +32,7 @@ jobs:
           - MegaCoreX:megaavr:4809
           - arduino:mbed_rp2040:pico
           - CubeCell:CubeCell:CubeCell-Board
+          - MegaCore:avr:1281
 
     runs-on: ubuntu-latest
     name: ${{ matrix.board }}
@@ -129,9 +130,13 @@ jobs:
             echo "::set-output name=index-url::--additional-urls https://mcudude.github.io/MegaCoreX/package_MCUdude_MegaCoreX_index.json"
 
           elif [[ "${{ contains(matrix.board, 'CubeCell:CubeCell') }}" == "true" ]]; then
-            # MegaCoreX
+            # CubeCell
             echo "::set-output name=index-url::--additional-urls https://resource.heltec.cn/download/package_CubeCell_index.json"
 
+          elif [[ "${{ contains(matrix.board, 'MegaCore:avr') }}" == "true" ]]; then
+            # MegaCore
+            echo "::set-output name=index-url::--additional-urls https://mcudude.github.io/MegaCore/package_MCUdude_MegaCore_index.json"
+
           fi
 
       - name: Install platform

README.md

@@ -66,6 +66,7 @@ SX127x, RFM9x, SX126x, RF69, SX1231, CC1101, nRF24L01, RFM2x, Si443x and SX128x
 
 * __MCUdude__
   * [__MegaCoreX__](https://github.com/MCUdude/MegaCoreX) - megaAVR-0 series (ATmega4809, ATmega3209 etc.)
+  * [__MegaCore__](https://github.com/MCUdude/MegaCore) - AVR (ATmega1281, ATmega640 etc.)
 
 * __Raspberry Pi__
   * [__RP2040__](https://github.com/arduino/ArduinoCore-mbed) - Raspberry Pi Pico and Arduino Nano RP2040 Connect