Revert "add yamllinter check (#124)" (#127)

This reverts commit bca3810496.

extensions/lang-english/.travis.yml

@@ -1,7 +0,0 @@
-language: bash
-
-before_script:
-  - go get github.com/sijad/yaml-translation-utils/yamllinter
-
-script:
-  - bash scripts/linter.sh

extensions/lang-english/scripts/linter.sh

@@ -1,32 +0,0 @@
-if ! [ -x "$(command -v yamllinter)" ]; then
-  echo 'Error: yamllinter is not installed.' >&2
-  exit 1
-fi
-
-GREEN='\033[0;32m'
-RED='\033[0;31m'
-NC='\033[0m'
-
-cd "./locale"
-
-RC=0
-
-for r in *.yml
-do
-  [ "$r" != "validation.yml" ] || continue
-
-  echo "Checking $r:"
-
-  yamllinter --file "$r" --level 2
-
-  if [ $? -eq 1 ]; then
-    RC=1
-    printf "${RED}⨉ faild${NC}\n"
-  else
-    printf "${GREEN}✓ passed${NC}\n"
-  fi
-
-  echo
-done
-
-exit $RC