[common] restore using environment proxies by default (#6553, #6609)

change 'proxy-env' default to 'true'

docs/configuration.rst

@@ -609,7 +609,7 @@ extractor.*.proxy-env
 Type
     ``bool``
 Default
-    ``false``
+    ``true``
 Description
     Collect proxy configuration information from environment variables
     (``HTTP_PROXY``, ``HTTPS_PROXY``, ``NO_PROXY``)

docs/gallery-dl.conf

@@ -22,7 +22,7 @@
         "tls12"         : true,
         "browser"       : null,
         "proxy"         : null,
-        "proxy-env"     : false,
+        "proxy-env"     : true,
         "source-address": null,
         "retries"       : 4,
         "retry-codes"   : [],

gallery_dl/extractor/common.py

@@ -348,7 +348,7 @@ class Extractor():
         ssl_options = ssl_ciphers = 0
 
         # .netrc Authorization headers are alwsays disabled
-        session.trust_env = True if self.config("proxy-env", False) else False
+        session.trust_env = True if self.config("proxy-env", True) else False
 
         browser = self.config("browser")
         if browser is None: