[+] replace deprecated golint linter with revive, closes #112

.golangci.yml

@@ -1,20 +1,10 @@
 linters:
   enable:
     - gocyclo
-    - golint
-    - misspell  
-  disable:
-    - structcheck # too many false positives
+    - misspell
+    - revive
 
 linters-settings:
   gocyclo:
     # minimal code complexity to report, 30 by default (but we recommend 10-20)
-    min-complexity: 20
-
-issues:
-  # List of regexps of issue texts to exclude, empty list by default.
-  # But independently from this option we use default exclude patterns,
-  # it can be disabled by `exclude-use-default: false`. To list all
-  # excluded by default patterns execute `golangci-lint run --help`
-  exclude:
-    - SA5008 # ignore staticcheck for go-flags  
+    min-complexity: 20