remove travis mentions in codebase

Travis is no longer used, let's ditch these.

README.md

@@ -79,8 +79,8 @@ make man
 ### Pull request gating
 
 Each pull request against `osbuild-composer` starts a series of automated
-tests. Tests run via GitHub Actions, Travis CI, and Jenkins. Each push to
-the pull request will launch theses tests automatically.
+tests. Tests run via GitHub Actions and Jenkins. Each push to the pull request
+will launch theses tests automatically.
 
 Jenkins only tests pull requests from members of the `osbuild` organization in
 GitHub. A member of the `osbuild` organization must say `ok to test` in a pull

cmd/osbuild-image-tests/aws.go

@@ -32,7 +32,7 @@ func getAWSCredentialsFromEnv() (*awsCredentials, error) {
 	region, regionExists := os.LookupEnv("AWS_REGION")
 	bucket, bucketExists := os.LookupEnv("AWS_BUCKET")
 
-	// Workaround Travis security feature. If non of the variables is set, just ignore the test
+	// If non of the variables is set, just ignore the test
 	if !akExists && !sakExists && !bucketExists && !regionExists {
 		return nil, nil
 	}

cmd/osbuild-image-tests/azuretest/azure.go

@@ -56,7 +56,7 @@ func GetAzureCredentialsFromEnv() (*azureCredentials, error) {
 	location, lExists := os.LookupEnv("AZURE_LOCATION")
 	resourceGroup, rgExists := os.LookupEnv("AZURE_RESOURCE_GROUP")
 
-	// Workaround Travis security feature. If non of the variables is set, just ignore the test
+	// If non of the variables is set, just ignore the test
 	if !saExists && !sakExists && !cExists && !siExists && !ciExists && !csExists && !tiExists && !lExists && !rgExists {
 		return nil, nil
 	}

internal/upload/azure/azure_test.go

@@ -38,7 +38,7 @@ func TestAzure_FileUpload(t *testing.T) {
 	fileName := "/tmp/testing-image.vhd"
 	var threads int = 4
 
-	// Workaround Travis security feature. If non of the variables is set, just ignore the test
+	// If non of the variables is set, just ignore the test
 	if saExists == false && sakExists == false && cnExists == false {
 		t.Log("No AZURE configuration provided, assuming that this is running in CI. Skipping the test.")
 		return