Remove old travis build status link from readme (#407)

* Remove old travis build status link from readme

* Remove unneeded go-version tag in CI
It is not supported inside golangci-lint-action and triggers a warning

.github/workflows/go.yml

@@ -22,7 +22,6 @@ jobs:
       uses: golangci/golangci-lint-action@v3.4.0
       with:
         version: "v1.45.2"
-        go-version: "1.18.x"
 
   test:
     strategy:

README.md

@@ -10,9 +10,6 @@
 </h6>
 
 <p align="center">
-  <a href="https://travis-ci.org/gabriel-vasile/mimetype">
-    <img alt="Build Status" src="https://travis-ci.org/gabriel-vasile/mimetype.svg?branch=master">
-  </a>
   <a href="https://pkg.go.dev/github.com/gabriel-vasile/mimetype">
     <img alt="Go Reference" src="https://pkg.go.dev/badge/github.com/gabriel-vasile/mimetype.svg">
   </a>