fix!: validate runner labels aren't padded with spaces

internal/pkg/labels/labels.go

@@ -31,6 +31,10 @@ func Parse(str string) (*Label, error) {
 		Schema: "docker",
 	}
 
+	if strings.TrimSpace(label.Name) != label.Name {
+		return nil, fmt.Errorf("invalid label %q: starting or ending with a space is invalid", label.Name)
+	}
+
 	if len(splits) >= 2 {
 		label.Schema = splits[1]
 		if label.Schema != SchemeHost && label.Schema != SchemeDocker && label.Schema != SchemeLXC {

internal/pkg/labels/labels_test.go

@@ -63,7 +63,6 @@ func TestParse(t *testing.T) {
 			},
 			wantErr: false,
 		},
-
 		{
 			args: "label1:host",
 			want: &Label{
@@ -78,12 +77,21 @@ func TestParse(t *testing.T) {
 			want:    nil,
 			wantErr: true,
 		},
-
 		{
 			args:    "label1:invalidscheme",
 			want:    nil,
 			wantErr: true,
 		},
+		{
+			args:    " label1:lxc://debian:buster",
+			want:    nil,
+			wantErr: true,
+		},
+		{
+			args:    "label1 :lxc://debian:buster",
+			want:    nil,
+			wantErr: true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.args, func(t *testing.T) {