Drop support for Vim prior to 8.2.1310

See #506 for details.

.github/workflows/vim.yml

@@ -18,8 +18,7 @@ jobs:
           - ubuntu-latest
         version:
           - nightly
-          - v8.2.0716 # Ubuntu 20.10 (2021/02/28)
-          - v8.1.2269 # Ubuntu 20.04 (2021/02/28)
+          - v8.2.1310 # https://github.com/lambdalisue/vim-fern/issues/506
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4

README.md

@@ -1,6 +1,6 @@
 # 🌿 vim-fern
 
-![Support Vim 8.1.2269 or above](https://img.shields.io/badge/support-Vim%208.1.2269%20or%20above-yellowgreen.svg)
+![Support Vim 8.2.1310 or above](https://img.shields.io/badge/support-Vim%208.2.1310%20or%20above-yellowgreen.svg)
 ![Support Neovim 0.4.4 or above](https://img.shields.io/badge/support-Neovim%200.4.4%20or%20above-yellowgreen.svg)
 [![Powered by vital.vim](https://img.shields.io/badge/powered%20by-vital.vim-80273f.svg)](https://github.com/vim-jp/vital.vim)
 [![Powered by vital-Whisky](https://img.shields.io/badge/powered%20by-vital--Whisky-80273f.svg)](https://github.com/lambdalisue/vital-Whisky)

plugin/fern.vim

@@ -23,8 +23,8 @@ if !has('nvim') && !has('patch-8.1.0994')
 elseif exists('+shellslash') && &shellslash
   call s:warn('"shellslash" option is not supported thus fern is disabled.')
   finish
-elseif !has('nvim') && !has('patch-8.1.2269')
-  call s:warn('Vim prior to 8.1.2269 is not supported and fern might not work properly.')
+elseif !has('nvim') && !has('patch-8.2.1310')
+  call s:warn('Vim prior to 8.2.1310 is not supported and fern might not work properly.')
 elseif has('nvim') && !has('nvim-0.4.4')
   call s:warn('Neovim prior to 0.4.4 is not supported and fern might not work properly.')
 endif