fix: remove gx support

Author: Stebalien

.travis.yml

@@ -10,7 +10,6 @@ env:
   global:
     - GOTFLAGS="-race"
   matrix:
-    - BUILD_DEPTYPE=gx
     - BUILD_DEPTYPE=gomod
 
 
@@ -24,7 +23,6 @@ script:
 
 cache:
   directories:
-    - $GOPATH/src/gx
     - $GOPATH/pkg/mod
     - /home/travis/.cache/go-build