Merge #19469: rpc: deprecate banscore field in getpeerinfo

41d55d3057 doc: getpeerinfo banscore deprecation release note (Jon Atack)
dd54e3796e test: getpeerinfo banscore deprecation test (Jon Atack)
8c7647b3fb rpc: deprecate banscore field in rpc getpeerinfo (Jon Atack)

Pull request description:

  Per https://github.com/bitcoin/bitcoin/pull/19219#discussion_r443074487 and https://github.com/bitcoin/bitcoin/pull/19219#issuecomment-652699592, this PR deprecates returning the `banscore` field in the `getpeerinfo` RPC, updates the help, adds a test, and updates the release notes. Related to #19464.

ACKs for top commit:
  fanquake:
    ACK 41d55d3057

Tree-SHA512: 8eca08332581e2fe191a2aafff6ba89ce39413f0491ed0de8b86577739f0ec430b1a8fbff2914b0f3138a229563dfcc1981c0cf5b7dd6061b5c48680a28423bc

test/functional/rpc_getpeerinfo_banscore_deprecation.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test deprecation of getpeerinfo RPC banscore field."""
+
+from test_framework.test_framework import BitcoinTestFramework
+
+
+class GetpeerinfoBanscoreDeprecationTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 2
+        self.extra_args = [[], ["-deprecatedrpc=banscore"]]
+
+    def run_test(self):
+        self.log.info("Test getpeerinfo by default no longer returns a banscore field")
+        assert "banscore" not in self.nodes[0].getpeerinfo()[0].keys()
+
+        self.log.info("Test getpeerinfo returns banscore with -deprecatedrpc=banscore")
+        assert "banscore" in self.nodes[1].getpeerinfo()[0].keys()
+
+
+if __name__ == "__main__":
+    GetpeerinfoBanscoreDeprecationTest().main()

test/functional/test_runner.py

@@ -243,6 +243,7 @@ BASE_SCRIPTS = [
     'feature_blocksdir.py',
     'feature_config_args.py',
     'rpc_getdescriptorinfo.py',
+    'rpc_getpeerinfo_banscore_deprecation.py',
     'rpc_help.py',
     'feature_help.py',
     'feature_shutdown.py',