package/python3: requires blake2 support in openssl

Fix the following build failure raised since bump to version 3.10.1 in
commit 25b1fc2898d68ddf2674b14c738045875fc5a2dc:

/home/buildroot/autobuild/instance-3/output-1/build/python3-3.10.1/Modules/_hashopenssl.c:244:22: error: implicit declaration of function 'EVP_blake2s256'; did you mean 'LN_blake2s256'? [-Werror=implicit-function-declaration]
  244 |             digest = EVP_blake2s256();
      |                      ^~~~~~~~~~~~~~
      |                      LN_blake2s256

Fixes:
 - http://autobuild.buildroot.org/results/9112571b75aebb0ba5032ef1b16226d9848f5184

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/python3/Config.in

@@ -90,6 +90,7 @@ config BR2_PACKAGE_PYTHON3_READLINE
 config BR2_PACKAGE_PYTHON3_SSL
 	bool "ssl"
 	select BR2_PACKAGE_OPENSSL
+	select BR2_PACKAGE_LIBOPENSSL_ENABLE_BLAKE2 if BR2_PACKAGE_LIBOPENSSL
 	help
 	  _ssl module for Python3 (required for https in urllib etc).