Use py39 miniconda version

Author: humitos

Dockerfile

@@ -17,7 +17,7 @@ ENV PYTHON_VERSION_39 3.9.1
 ENV PYTHON_VERSION_310 3.10.0b3
 ENV PYPY_VERSION_35 pypy3.5-7.0.0
 # Latest miniconda version is Miniconda3-py39_4.10.1, but it's not available for x86_64
-ENV CONDA_PYTHON_VERSION py38
+ENV CONDA_PYTHON_VERSION py39
 ENV CONDA_VERSION 4.9.2
 LABEL python.version_27=$PYTHON_VERSION_27
 LABEL python.version_35=$PYTHON_VERSION_35