Update i2s_microphone data value (#3732)

According to here: https://github.com/esphome/esphome/blob/4fcb26d69dd4b245023df25d63946e5a974a391c/esphome/components/i2s_audio/microphone/i2s_audio_microphone.cpp#L138 it seems to be an int16_t

Co-authored-by: H. Árkosi Róbert <[email protected]>

components/microphone/index.rst

@@ -58,7 +58,7 @@ Microphone Triggers
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 This trigger will fire when new data is received from the microphone.
-The data is available as a ``std::vector<uint8_t>`` in the variable ``x``.
+The data is available as a ``std::vector<int16_t>`` in the variable ``x``.
 
 .. code-block:: yaml