Drop support for go v1.11 and v1.12

Author: mennanov

.drone.yml

@@ -53,31 +53,6 @@ steps:
       - go vet ./...
       - go test ./...
 
----
-kind: pipeline
-name: go1.12
-type: docker
-
-steps:
-  - name: test
-    image: golang:1.12
-    commands:
-      - go vet ./...
-      - go test ./...
-
-
----
-kind: pipeline
-name: go1.11
-type: docker
-
-steps:
-  - name: test
-    image: golang:1.11
-    commands:
-      - go vet ./...
-      - go test ./...
-
 ---
 kind: pipeline
 name: lint