fix: specify output filename in go build command

The build command 'go build -v ./cmd' was trying to create an executable
named 'cmd' which conflicts with the existing 'cmd' directory.

Fix by specifying output filename: 'go build -v -o flashduty-runner ./cmd'

Author: ysyneu

.github/workflows/go.yml

@@ -30,7 +30,7 @@ jobs:
         run: go test -race -coverprofile=coverage.out ./...
 
       - name: Build
-        run: go build -v ./cmd
+        run: go build -v -o flashduty-runner ./cmd
 
       - name: Upload coverage
         if: matrix.os == 'ubuntu-latest'