Fix commandline argument --burst-disable-compilation is to be passe…

…d with two dashes

see: https://docs.unity3d.com/Packages/[email protected]/manual/UsingCodeCoverage.html#using-code-coverage-with-burst-compiler

Makefile

@@ -57,7 +57,7 @@ define cover
   $(UNITY) \
     $(call base_arguments) \
     $(call test_arguments) \
-    -burst-disable-compilation \
+    --burst-disable-compilation \
     -debugCodeOptimization \
     -enableCodeCoverage \
     -coverageResultsPath $(LOG_DIR) \