ESPAsyncTCP.h: remove unnecessary semicolon

[MacDada]

Fixes a warning when compiling with -Wpedantic:

.pio/libdeps/nodemcu/ESPAsyncTCP/src/ESPAsyncTCP.h:34:2: warning: extra ';' [-Wpedantic]
   34 | };
      |  ^

[MacDada]

@me-no-dev I cannot run the github workflow checks – it needs your approval.

Could please spend the 5 minutes required to merge this PR? This is a really simple change, should be a no–brainer, while being beneficial for all :)