Update bme280.rst with CSB pin hint

Add warning to check connection diagram, since leaving CSB non-pulled will result in dropping out of I2C mode after some time after start.

components/sensor/bme280.rst

@@ -13,6 +13,8 @@ is used in *Forced Mode* where measurement is performed and then
 the sensor returns to sleep mode until next measurement. The :ref:`I²C <i2c>` or :ref:`SPI <spi>` is
 required to be set up in your configuration for this sensor to work.
 
+**Note:** In :ref:`I²C <i2c>` mode pulling CSB to 3V is recommended, in order to avoid ``[E][sensor.bme280:155]: Communication with BME280 failed!`` error. See the *Connection diagram* chapter in datasheet above.
+
 .. figure:: images/bme280-full.jpg
     :align: center
     :width: 50.0%