Change best bot to MCTS (UCT), 100 rollouts, greedy rollout

```
[SUMMARY]
[challenge1]: 0 Sampling wins, 6 ties, 19
Uct100RolloutsSqrt2CGreedyNotDead wins --
Uct100RolloutsSqrt2CGreedyNotDead better than Sampling (p-value=0.000)
[challenge2]: 0 Sampling wins, 25 ties, 0
Uct100RolloutsSqrt2CGreedyNotDead wins -- not significant (p-value=1.000)
[challenge3]: 0 Sampling wins, 21 ties, 4
Uct100RolloutsSqrt2CGreedyNotDead wins -- not significant (p-value=0.125)
[challenge4]: 0 Sampling wins, 21 ties, 4
Uct100RolloutsSqrt2CGreedyNotDead wins -- not significant (p-value=0.125)
[challenge5]: 0 Sampling wins, 12 ties, 13
Uct100RolloutsSqrt2CGreedyNotDead wins --
Uct100RolloutsSqrt2CGreedyNotDead better than Sampling (p-value=0.000)
[challenge6]: 0 Sampling wins, 2 ties, 23
Uct100RolloutsSqrt2CGreedyNotDead wins --
Uct100RolloutsSqrt2CGreedyNotDead better than Sampling (p-value=0.000)
Sampling: 0 wins, ties: 87, Uct100RolloutsSqrt2CGreedyNotDead: 63 wins
-- Uct100RolloutsSqrt2CGreedyNotDead better than Sampling (p-value=0.000)
```

bot/src/search.rs

@@ -127,7 +127,7 @@ pub struct Bot<'a> {
 
 impl Bot<'_> {
     pub fn new_best(state: State, seed: u64) -> Self {
-        Self::new(state, seed, BotName::Sampling)
+        Self::new(state, seed, BotName::Uct100RolloutsSqrt2CGreedyNotDead)
     }
 
     pub fn new(state: State, seed: u64, name: BotName) -> Self {