Tilt environment: Fix ClickHouse docker image selection (#4486)

After #4478, the last row in
flow CI definition for the version matrix was not `latest` anymore but
`stable`.

This row is used by the Tilt environment to select the default target
version for ClickHouse. `stable` is not a valid tag hence Tilt
environments broke

Author: pfcoperez

generate-test-environment.sh

@@ -26,7 +26,7 @@ if [ -z "$MONGODB_VERSION" ]; then
 fi;
 
 if [ -z "$CLICKHOUSE_VERSION" ]; then
-    CLICKHOUSE_VERSION=$(echo "$VERSIONS" | yq -r '.ch')
+    CLICKHOUSE_VERSION="latest"
 fi;
 
 if [ -z "$POSTGRES_VERSION" ] || [ -z "$MYSQL_VERSION" ] || [ -z "$MONGODB_VERSION" ] || [ -z "$CLICKHOUSE_VERSION" ]; then
@@ -48,4 +48,4 @@ echo "" >> "$ENVIRONMENT_FILE"
 echo MONGODB_IMAGE="mongo:${MONGODB_VERSION}" >> "$ENVIRONMENT_FILE"
 echo CLICKHOUSE_IMAGE="clickhouse/clickhouse-server:${CLICKHOUSE_VERSION}" >> "$ENVIRONMENT_FILE"
 echo POSTGRES_IMAGE="imresamu/postgis:${POSTGRES_VERSION}-3.5-alpine" >> "$ENVIRONMENT_FILE"
-echo MYSQL_IMAGE="mysql:${MYSQL_VERSION}" >> "$ENVIRONMENT_FILE"
+echo MYSQL_IMAGE="mysql:${MYSQL_VERSION}" >> "$ENVIRONMENT_FILE"