docs: fix incorrect env var description

Author: stigok

CHANGELOG.md

@@ -5,6 +5,9 @@
 1. [#241](https://github.com/influxdata/influxdb-client-python/pull/241): Add detail error message for not supported type of `Point.field`
 1. [#238](https://github.com/influxdata/influxdb-client-python/pull/238): Add possibility to specify default `timezone` for datetimes without `tzinfo`
 
+### Documentation
+1. [#255](https://github.com/influxdata/influxdb-client-python/pull/255): Fix invalid description for env var `INFLUXDB_V2_CONNECTION_POOL_MAXSIZE`
+
 ## 1.17.0 [2021-04-30]
 
 ### Features

README.rst

@@ -201,7 +201,7 @@ Supported properties are:
 - ``INFLUXDB_V2_TIMEOUT`` - socket timeout in ms (default value is 10000)
 - ``INFLUXDB_V2_VERIFY_SSL`` - set this to false to skip verifying SSL certificate when calling API from https server
 - ``INFLUXDB_V2_SSL_CA_CERT`` - set this to customize the certificate file to verify the peer
-- ``INFLUXDB_V2_CONNECTION_POOL_MAXSIZE`` - set this to customize the certificate file to verify the peer
+- ``INFLUXDB_V2_CONNECTION_POOL_MAXSIZE`` - set the number of connections to save that can be reused by urllib3
 
 .. code-block:: python