runtime: hard code materialize-bigquery in ser_policy

BigQuery actually has a limit of 20MiB on an individual row that can be returned
via its Query API. Although we can store a row with a `flow_document` that
large, we then can't read it back out using the conventional query mechanism the
materialization connector currently uses.

This adds `materialize-bigquery` to the list of connectors that use
`ser_policy`, which should generally reduce how often we store rows that are
excessively large.

crates/runtime/src/materialize/task.rs

@@ -31,6 +31,7 @@ impl Task {
         // that don't handle large strings very well. This should be negotiated via connector protocol.
         // See go/runtime/materialize.go:135
         let ser_policy = if [
+            "ghcr.io/estuary/materialize-bigquery",
             "ghcr.io/estuary/materialize-snowflake",
             "ghcr.io/estuary/materialize-redshift",
             "ghcr.io/estuary/materialize-sqlite",