Add shellscript filenamePatterns for .env.* (microsoft#173426)

* Add shellscript `filenamePatterns` for `.env*`

In some cases, projects use `.env` files such as `.env.development`
or `.env.production` or similar things.

Adding this to extensions/shellscript/package.json as a
`filenamePatterns` avoids developers having to add specific
`"files.associations"` to their VS Code settings files.

Fixes microsoft#173425

* Change pattern from .env* to .env.*

extensions/shellscript/package.json

@@ -67,6 +67,9 @@
           "bashrc_Apple_Terminal",
           "zshrc_Apple_Terminal"
         ],
+        "filenamePatterns": [
+          ".env.*"
+        ],
         "firstLine": "^#!.*\\b(bash|fish|zsh|sh|ksh|dtksh|pdksh|mksh|ash|dash|yash|sh|csh|jcsh|tcsh|itcsh).*|^#\\s*-\\*-[^*]*mode:\\s*shell-script[^*]*-\\*-",
         "configuration": "./language-configuration.json",
         "mimetypes": [