package/python-lxml: security bump to version 4.6.3

Fix CVE-2021-28957: lxml 4.6.2 allows XSS. It places the HTML action
attribute into defs.link_attrs (in html/defs.py) for later use in input
sanitization, but does not do the same for the HTML5 formaction
attribute.

https://github.com/lxml/lxml/blob/lxml-4.6.3/CHANGES.txt

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/python-lxml/python-lxml.hash

@@ -1,5 +1,5 @@
 # Locally computed
-sha256  cd11c7e8d21af997ee8079037fff88f16fda188a9776eb4b81c7e4c9c0a7d7fc  lxml-4.6.2.tar.gz
+sha256  39b78571b3b30645ac77b95f7c69d1bffc4cf8c3b157c435a34da72e78c82468  lxml-4.6.3.tar.gz
 sha256  41d49dd406aa0e1548a6d5f21a30d6bf638b3cd96eb7289dd348d83ed2e40392  LICENSES.txt
 sha256  69edb445c1335a8312d4c09271847e9956d84f0d9f724d125340cc3fad767b2a  doc/licenses/BSD.txt
 sha256  0497ae8138811ef4466ede653bab7a59feb3d3c14f9ed50fc33a00aeb5bec32e  doc/licenses/elementtree.txt

package/python-lxml/python-lxml.mk

@@ -4,8 +4,8 @@
 #
 ################################################################################
 
-PYTHON_LXML_VERSION = 4.6.2
-PYTHON_LXML_SITE = https://files.pythonhosted.org/packages/db/f7/43fecb94d66959c1e23aa53d6161231dca0e93ec500224cf31b3c4073e37
+PYTHON_LXML_VERSION = 4.6.3
+PYTHON_LXML_SITE = https://files.pythonhosted.org/packages/e5/21/a2e4517e3d216f0051687eea3d3317557bde68736f038a3b105ac3809247
 PYTHON_LXML_SOURCE = lxml-$(PYTHON_LXML_VERSION).tar.gz
 
 # Not including the GPL, because it is used only for the test scripts.