Fix 604

[Oaroomy]

Changed KademliaProtocol.BootstrapAsync exception type from SwarmException to PeerDiscoveryException.

This pr fixes #604

[moreal]

It seems tests failed. 😿

https://dev.azure.com/planetarium/libplanet/_build/results?buildId=2533&view=logs

[codecov]

Codecov Report

Merging #726 into master will increase coverage by 1.52%.
The diff coverage is 37.5%.

@@            Coverage Diff             @@
##           master     #726      +/-   ##
==========================================
+ Coverage   85.09%   86.62%   +1.52%     
==========================================
  Files         197      222      +25     
  Lines       18060    18753     +693     
==========================================
+ Hits        15368    16244     +876     
+ Misses       1541     1352     -189     
- Partials     1151     1157       +6

Impacted Files	Coverage Δ
Libplanet.Tests/Net/SwarmTest.cs	95.86% <100%> (ø)	⬆️
Libplanet/Net/Protocols/PeerDiscoveryException.cs	25% <25%> (ø)
Libplanet/Net/Protocols/KademliaProtocol.cs	65.26% <50%> (-0.53%)	⬇️
....Stun.Tests/Stun/Messages/ConnectionAttemptTest.cs	100% <0%> (ø)
...Stun/Messages/ConnectionBindSuccessResponseTest.cs	100% <0%> (ø)
...Tests/Stun/Messages/AllocateSuccessResponseTest.cs	100% <0%> (ø)
...un.Tests/Stun/Messages/RefreshErrorResponseTest.cs	100% <0%> (ø)
...Stun.Tests/Stun/Attributes/MessageIntegrityTest.cs	100% <0%> (ø)
...et.Stun.Tests/Stun/Messages/AllocateRequestTest.cs	100% <0%> (ø)
... and 34 more