Retract tags taken by mistake from kiwicom/gocql

Retract v1.8.0, v1.8.1, v1.9.0, v1.10.0 - tags mistakenly taken from
kiwicom/gocql, which are not actual releases made in scylladb/gocql.

Even though those tags were removed from scylladb/gocql (see #110),
some Go module mirrors have already fetched them:

  $ go list -m --versions github.com/scylladb/gocql
  github.com/scylladb/gocql v1.0.0 v1.0.1 v1.0.2 v1.0.3 v1.0.4 v1.1.0 v1.2.0 v1.2.1 v1.3.0-rc.1 v1.3.0 v1.3.1 v1.3.2 v1.3.3 v1.3.4 v1.4.0 v1.4.1 v1.4.2 v1.4.3 v1.5.0 v1.6.0 v1.7.0 v1.7.1 v1.7.2 v1.7.3 v1.8.0 v1.8.1 v1.9.0 v1.10.0

As we can't control those mirrors, they will always return an incorrect
version of gocql, even if we release "new" 1.9.0, 1.10.0.

Subsequent to merging of this patch, version v1.11.0 of scylladb/gocql
will be released.

go.mod

@@ -13,4 +13,11 @@ require (
 	sigs.k8s.io/yaml v1.3.0
 )
 
+retract (
+    v1.8.0  // tag from kiwicom/gocql added by mistake to scylla/gocql
+    v1.8.1  // tag from kiwicom/gocql added by mistake to scylla/gocql
+    v1.9.0  // tag from kiwicom/gocql added by mistake to scylla/gocql
+    v1.10.0 // tag from kiwicom/gocql added by mistake to scylla/gocql
+)
+
 go 1.13