Dashes not underscores

.github/workflows/main_matrix.yml

@@ -38,8 +38,8 @@ jobs:
           - board: rak4631_eink
           - board: t-echo
           - board: nano-g1
-          - board: m5stack_core
-          - board: m5stack_coreink
+          - board: m5stack-core
+          - board: m5stack-coreink
           
     runs-on: ubuntu-latest
     steps:
@@ -95,8 +95,8 @@ jobs:
           - board: tbeam0.7
           - board: meshtastic-diy-v1
           - board: nano-g1
-          - board: m5stack_core
-          - board: m5stack_coreink
+          - board: m5stack-core
+          - board: m5stack-coreink
 
     runs-on: ubuntu-latest
     steps: