vagrant: rather use python 3.6.2 than 3.6.0

coverage package otherwise causes an issue with sqlite and py360.
py361 seems to have other trouble, so let's use py362.

Vagrantfile

@@ -233,7 +233,7 @@ def install_pythons(boxname)
   return <<-EOF
     . ~/.bash_profile
     pyenv install 3.5.3  # tests, 3.5.3 is first to support openssl 1.1
-    pyenv install 3.6.0  # tests
+    pyenv install 3.6.2  # tests
     pyenv install 3.7.0  # tests
     pyenv install 3.8.0  # tests
     pyenv install 3.5.9  # binary build, use latest 3.5.x release
@@ -315,8 +315,8 @@ def run_tests(boxname)
     . ../borg-env/bin/activate
     if which pyenv 2> /dev/null; then
       # for testing, use the earliest point releases of the supported python versions:
-      pyenv global 3.5.3 3.6.0 3.7.0 3.8.0
-      pyenv local 3.5.3 3.6.0 3.7.0 3.8.0
+      pyenv global 3.5.3 3.6.2 3.7.0 3.8.0
+      pyenv local 3.5.3 3.6.2 3.7.0 3.8.0
     fi
     # otherwise: just use the system python
     if which fakeroot 2> /dev/null; then