chore(tools): Update promtail image version (#7770)

**What this PR does / why we need it**:
update promtail version on `tools/promtail.sh` which generates promtail
config for kubernetes

**Which issue(s) this PR fixes**:
Fixes #NA

**Special notes for your reviewer**:
This image is part of latest loki 2.7.0 release and[ it does exists
](https://hub.docker.com/layers/grafana/promtail/2.7.0/images/sha256-d54b599ea154df295486068f1545731bd5ab9790602d8518816c9285eec3df5e?context=repo)


**Checklist**

tools/promtail.sh

@@ -6,7 +6,7 @@ INSTANCEURL="${3:-}"
 NAMESPACE="${4:-default}"
 CONTAINERROOT="${5:-/var/lib/docker}"
 PARSER="${6:-- docker:}"
-VERSION="${PROMTAIL_VERSION:-2.6.1}"
+VERSION="${PROMTAIL_VERSION:-2.7.0}"
 
 if [ -z "${INSTANCEID}" ] || [ -z "${APIKEY}" ] || [ -z "${INSTANCEURL}" ] || [ -z "${NAMESPACE}" ] || [ -z "${CONTAINERROOT}" ] || [ -z "${PARSER}" ]; then
     echo "usage: $0 <instanceId> <apiKey> <url> [<namespace>[<container_root_path>[<parser>]]]"