turn github repo name into lowercase for namespace compatibility

api/server/handlers/environment/enable_pull_request.go

@@ -101,7 +101,7 @@ func (c *EnablePullRequestHandler) ServeHTTP(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	namespace := fmt.Sprintf("pr-%d-%s", request.Number, strings.ReplaceAll(env.GitRepoName, "_", "-"))
+	namespace := fmt.Sprintf("pr-%d-%s", request.Number, strings.ToLower(strings.ReplaceAll(env.GitRepoName, "_", "-")))
 
 	// create the deployment
 	depl, err := c.Repo().Environment().CreateDeployment(&models.Deployment{

internal/integrations/ci/actions/steps.go

@@ -55,7 +55,7 @@ func getCreatePreviewEnvStep(
 			"project": fmt.Sprintf("%d", projectID),
 			"token":   fmt.Sprintf("${{ secrets.%s }}", porterTokenSecretName),
 			"namespace": fmt.Sprintf("pr-${{ github.event.inputs.pr_number }}-%s",
-				strings.ReplaceAll(repoName, "_", "-")),
+				strings.ToLower(strings.ReplaceAll(repoName, "_", "-"))),
 			"pr_id":           "${{ github.event.inputs.pr_number }}",
 			"pr_name":         "${{ github.event.inputs.pr_title }}",
 			"installation_id": fmt.Sprintf("%d", gitInstallationID),