Can't properly install plugin with branch specified

Output from _vim-plug_:
```none
5 Updated. Elapsed time: 2.218548 sec.
4 [===================x]
3
2 - Finishing ... Done!
1 x vim-taggatron:
6 fatal: invalid reference: issue/10
```
[The plugin & branch](https://github.com/Dica-Developer/vim-taggatron/tree/issue/10), which Git and GitHub seem to accept without issue. The plugin does actually install but the output of `git branch` in `~/.vim/plugged/vim-taggatron` is just this:
```none
* master
```
I have to checkout the branch manually with `git checkout issue/10`:
```none
Branch issue/10 set up to track remote branch issue/10 from origin.
Switched to a new branch 'issue/10'
```
I don't know if me doing that will mess up future updates.

------------------------------

```none
VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Mar 27 2020 16:45:06)
Included patches: 1-460
Compiled by Roy
Huge version without GUI. Features included (+) or not (-):
+acl +channel +cscope +ex_extra -hangul_input +lispindent -mouse_gpm +netbeans_intg +python/dyn +spell +terminal +vertsplit +X11
+arabic +cindent +cursorbind +extra_search +iconv +listcmds -mouse_jsbterm +num64 +python3/dyn +startuptime +terminfo +virtualedit +xfontset
+autocmd +clientserver +cursorshape -farsi +insert_expand +localmap +mouse_netterm +packages +quickfix +statusline +termresponse +visual -xim
+autochdir +clipboard +dialog_con +file_in_path +job -lua +mouse_sgr +path_extra +reltime -sun_workshop +textobjects +visualextra +xpm
-autoservername +cmdline_compl +diff +find_in_path +jumplist +menu -mouse_sysmouse +perl +rightleft +syntax +textprop +viminfo +xsmp_interact
-balloon_eval +cmdline_hist +digraphs +float +keymap +mksession +mouse_urxvt +persistent_undo -ruby +tag_binary +timers +vreplace +xterm_clipboard
+balloon_eval_term +cmdline_info -dnd +folding +lambda +modify_fname +mouse_xterm +popupwin +scrollbind -tag_old_static +title +wildignore -xterm_save
-browse +comments -ebcdic -footer +langmap +mouse +multi_byte +postscript +signs -tag_any_white -toolbar +wildmenu
++builtin_terms +conceal +emacs_tags +fork() +libcall -mouseshape +multi_lang +printer +smartindent -tcl +user_commands +windows
+byte_offset +cryptv +eval +gettext +linebreak +mouse_dec -mzscheme +profile -sound +termguicolors +vartabs +writebackup
system vimrc file: "$VIM/vimrc"
user vimrc file: "$HOME/.vimrc"
2nd user vimrc file: "~/.vim/vimrc"
user exrc file: "$HOME/.exrc"
defaults file: "$VIMRUNTIME/defaults.vim"
fall-back for $VIM: "/usr/local/share/vim"
Compilation: gcc -std=gnu99 -c -I. -Iproto -DHAVE_CONFIG_H -O -I/usr/lib64/perl5/CORE/ -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1 -I/usr/include64
Linking: gcc -std=gnu99 -L/usr/lib64 -Wl,--enable-new-dtags -Wl,-rpath,/usr/lib64/perl5/CORE -L/usr/local/lib -Wl,--as-needed -o vim -lSM -lICE -lXpm -lXt -lX11 -lSM -lICE -lm -ltinfo -lnsl -ldl -Wl,--enable-new-dtags -Wl,-rpath,/usr/lib64/perl5/CORE -fstack-protector -L/usr/lib64/perl5/CORE -lperl -lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
```

- Type:
- [x] Bug
- [ ] Enhancement
- [ ] Feature Request
- [ ] Question
- OS:
- [ ] All/Other
- [x] Linux
- [ ] OS X
- [ ] Windows
- Vim:
- [x] Terminal Vim
- [ ] GVim
- [ ] Neovim