Use double quotes for env values (#1617)

Updates the `to_env` filter to use double quotes for values instead of
single quotes. This preserves literal newline character as a multiline
string.

Co-authored-by: Pacotole <[email protected]>

Author: swalkinshaw

lib/trellis/plugins/filter/filters.py

@@ -5,7 +5,7 @@
 from jinja2 import pass_environment
 
 def to_env(dict_value):
-    envs = ["{0}='{1}'".format(key.upper(), str(value).replace("'","\\'")) for key, value in sorted(dict_value.items())]
+    envs = ['{0}="{1}"'.format(key.upper(), str(value).replace('"', '\\"')) for key, value in sorted(dict_value.items())]
     return "\n".join(envs)
 
 def underscore(value):