Modify bridgepool assignments processor and increment document version

Right now we are publishing bridge pool assignments documents with version 1.0 (https://gitlab.torproject.org/tpo/network-health/metrics/collector/-/blob/master/src/main/java/org/torproject/metrics/collector/bridgepools/BridgePoolAssignmentsProcessor.java#L333).

There has been some changes to the docs and I think we should increment the version to 1.1 (tpo/anti-censorship/rdsys!280 (merged))