diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..6b8710a
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1 @@
+.git
diff --git a/Dockerfile b/Dockerfile
index 4db8a52..b29fbb2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,7 +7,7 @@ WORKDIR /app
 COPY go.mod go.sum /app/
 RUN go mod download
 
-COPY *.go /app/
+COPY . /app/
 RUN go build -o app .
 
 FROM docker.io/alpine:3.22
diff --git a/go.mod b/go.mod
index 83158b7..4825266 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,4 @@ module code.geekeey.de/actions/checkout
 
 go 1.23.2
 
-require code.geekeey.de/actions/sdk v1.2.0
+require code.geekeey.de/actions/sdk v1.5.0
diff --git a/go.sum b/go.sum
index 6a21fc7..b25cf65 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,2 @@
-code.geekeey.de/actions/sdk v1.2.0 h1:qQvOdTBtZVpR1xATNnApeiW78y34Jh83OjsQg1ajPjA=
-code.geekeey.de/actions/sdk v1.2.0/go.mod h1:7iIOi3YUmdDe2BCz9s59wK1t0Ckec34e664q+TOreiE=
+code.geekeey.de/actions/sdk v1.5.0 h1:7Ly8QsBniiwDVbv2Gm14l28+ccK1Z9fVUqsPHw9lSMg=
+code.geekeey.de/actions/sdk v1.5.0/go.mod h1:7iIOi3YUmdDe2BCz9s59wK1t0Ckec34e664q+TOreiE=
diff --git a/main.go b/main.go
index 9fff017..f410c1f 100644
--- a/main.go
+++ b/main.go
@@ -32,8 +32,6 @@ type CheckoutAction struct {
 }
 
 func (action *CheckoutAction) setup() error {
-	var err error
-
 	action.repository = action.GetInput("repository")
 	if len(action.repository) == 0 {
 		return fmt.Errorf("input 'repository': is empty") // something like '<server>/<owner>/<repo>.git'
@@ -48,7 +46,8 @@ func (action *CheckoutAction) setup() error {
 	if len(action.reference) == 0 {
 		return fmt.Errorf("input 'ref': is empty") // something like 'HEAD'
 	}
-	return err
+
+	return nil
 }
 
 func (action *CheckoutAction) Run(ctx context.Context) error {