Strip -<suffix> when autodetecting shell (#377)

For example bash-5.1, bash-static.

Author: scop

bin/pyenv-virtualenv-init

@@ -45,6 +45,7 @@ if [ -z "$shell" ]; then
   shell="${shell%% *}"
   shell="${shell:-$SHELL}"
   shell="${shell##*/}"
+  shell="${shell%%-*}"
 fi
 
 if [ -z "$print" ]; then