Ping logger concurrent map write

[corverroos]

Problem to solve

Encountered the following error running docker compose:

charon-docker-compose-node0-1       | fatal error: concurrent map writes
charon-docker-compose-node0-1       |
charon-docker-compose-node0-1       | goroutine 12 [running]:
charon-docker-compose-node0-1       | runtime.throw({0x12f0ae1, 0xc000dbbe70})
charon-docker-compose-node0-1       | 	/opt/homebrew/Cellar/go/1.17.6/libexec/src/runtime/panic.go:1198 +0x71 fp=0xc000dbbe28 sp=0xc000dbbdf8 pc=0x437051
charon-docker-compose-node0-1       | runtime.mapassign_faststr(0x102fcc0, 0xc000c75c80, {0xc000252360, 0x27})
charon-docker-compose-node0-1       | 	/opt/homebrew/Cellar/go/1.17.6/libexec/src/runtime/map_faststr.go:294 +0x38b fp=0xc000dbbe90 sp=0xc000dbbe28 pc=0x4131ab
charon-docker-compose-node0-1       | github.com/obolnetwork/charon/p2p.newPingLogger.func1({0x15a99d0, 0xc000d8e9c0}, {0xc000252360, 0x27}, {0x0, 0x0})
charon-docker-compose-node0-1       | 	/Users/corver/repos/charon/p2p/ping.go:98 +0xf3 fp=0xc000dbbf20 sp=0xc000dbbe90 pc=0xe5c373
charon-docker-compose-node0-1       | github.com/obolnetwork/charon/p2p.pingPeer({0x15a99d0, 0xc000d8e9c0}, 0xc0001a8e20, {0xc000252360, 0x27}, 0xc000d9a160, 0x0)
charon-docker-compose-node0-1       | 	/Users/corver/repos/charon/p2p/ping.go:61 +0x15d fp=0xc000dbbf98 sp=0xc000dbbf20 pc=0xe5c01d
charon-docker-compose-node0-1       | github.com/obolnetwork/charon/p2p.NewPingService.func1·dwrap·1()

Proposed Solution

Add a mutex to the stateful ping logger in charon/p2p/ping.go:82#newPingLogger