add .editorconfig and remove static indent shfmt setting from lint action

.editorconfig

@@ -0,0 +1,9 @@
+[*]
+indent_style = space
+indent_size = 4
+tab_width = 8
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+function_next_line = true
+switch_case_indent = true

.github/workflows/lint.yml

@@ -8,7 +8,7 @@ on:
     paths:
       - 'xo-install.sh'
       - 'xo-vm-import.sh'
-    
+
 jobs:
   shellcheck:
     runs-on: ubuntu-latest
@@ -16,11 +16,11 @@ jobs:
     - uses: actions/checkout@v2
     - name: run shellcheck
       uses: ludeeus/action-shellcheck@1.1.0
-    
+
     - name: run shfmt
       uses: luizm/action-sh-checker@v0.3.0
       env:
-        SHFMT_OPTS: -i 4 -d
+        SHFMT_OPTS: -d
       with:
         sh_checker_comment: false
         sh_checker_shellcheck_disable: true