New flag --incompatible_no_attr_license to disable `attr.license` function

#6420

RELNOTES:
  The function `attr.license` is deprecated and will be removed.
  It can be disabled now with `--incompatible_no_attr_license`.
PiperOrigin-RevId: 218910996
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
index f09875c..5af8f65 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkSemantics.java
@@ -48,6 +48,7 @@
         SkylarkSemantics::incompatibleDisableObjcProviderResources),
     INCOMPATIBLE_NO_TARGET_OUTPUT_GROUP(
         SkylarkSemantics::incompatibleNoTargetOutputGroup),
+    INCOMPATIBLE_NO_ATTR_LICENSE(SkylarkSemantics::incompatibleNoAttrLicense),
     NONE(null);
 
     // Using a Function here makes the enum definitions far cleaner, and, since this is
@@ -152,6 +153,8 @@
 
   public abstract boolean incompatibleNewActionsApi();
 
+  public abstract boolean incompatibleNoAttrLicense();
+
   public abstract boolean incompatibleNoOutputAttrDefault();
 
   public abstract boolean incompatibleNoSupportToolsInActionInputs();
@@ -212,6 +215,7 @@
           .incompatibleExpandDirectories(false)
           .incompatibleGenerateJavaCommonSourceJar(false)
           .incompatibleNewActionsApi(false)
+          .incompatibleNoAttrLicense(false)
           .incompatibleNoOutputAttrDefault(false)
           .incompatibleNoSupportToolsInActionInputs(false)
           .incompatibleNoTargetOutputGroup(false)
@@ -276,6 +280,8 @@
 
     public abstract Builder incompatibleNewActionsApi(boolean value);
 
+    public abstract Builder incompatibleNoAttrLicense(boolean value);
+
     public abstract Builder incompatibleNoOutputAttrDefault(boolean value);
 
     public abstract Builder incompatibleNoSupportToolsInActionInputs(boolean value);