errors: rewrite errors to follow go best practices

Errors should not start capitalised and they should not contain the word error
or state that they "failed" as we already know it is an error

Signed-off-by: Kristoffer Dalby <kristoffer@dalby.cc>

integration/integrationutil/util.go

@@ -59,17 +59,17 @@ func WriteFileToContainer(
 
 	err := tarWriter.WriteHeader(header)
 	if err != nil {
-		return fmt.Errorf("failed write file header to tar: %w", err)
+		return fmt.Errorf("writing file header to tar: %w", err)
 	}
 
 	_, err = io.Copy(tarWriter, file)
 	if err != nil {
-		return fmt.Errorf("failed to copy file to tar: %w", err)
+		return fmt.Errorf("copying file to tar: %w", err)
 	}
 
 	err = tarWriter.Close()
 	if err != nil {
-		return fmt.Errorf("failed to close tar: %w", err)
+		return fmt.Errorf("closing tar: %w", err)
 	}
 
 	// Ensure the directory is present inside the container
@@ -79,7 +79,7 @@ func WriteFileToContainer(
 		[]string{},
 	)
 	if err != nil {
-		return fmt.Errorf("failed to ensure directory: %w", err)
+		return fmt.Errorf("ensuring directory: %w", err)
 	}
 
 	err = pool.Client.UploadToContainer(