net/exabgp4: Update to 4.2.13

Allow Python 3.6+

re: https://github.com/Exa-Networks/exabgp/releases/tag/4.2.13

Approved by:	zi (maintainer) via private communication

net/exabgp4/Makefile

@@ -1,7 +1,7 @@
 # Created by: Ryan Steinmetz <zi@FreeBSD.org>
 
 PORTNAME=	exabgp
-PORTVERSION=	4.2.11
+PORTVERSION=	4.2.13
 PORTREVISION=	1
 CATEGORIES=	net
 MASTER_SITES=	GH \
@@ -15,7 +15,7 @@ COMMENT=	BGP engine and route injector
 LICENSE=	BSD3CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENCE.txt
 
-USES=		python:3.6-3.7 shebangfix
+USES=		python:3.6+ shebangfix
 USE_PYTHON=	distutils autoplist
 
 CONFLICTS_INSTALL=	exabgp-[0-9]*

net/exabgp4/distinfo

@@ -1,3 +1,3 @@
-TIMESTAMP = 1598383902
-SHA256 (Exa-Networks-exabgp-4.2.11_GH0.tar.gz) = 3a291cf4906671b6c929b601ca41340ffb3b4e4ccd50ac41a9cbc32777ee39ca
-SIZE (Exa-Networks-exabgp-4.2.11_GH0.tar.gz) = 2931753
+TIMESTAMP = 1628777729
+SHA256 (Exa-Networks-exabgp-4.2.13_GH0.tar.gz) = 13add263c895fe4459bd4b62b92a1299c7039dcd99d3b074464e3c19029ad5e7
+SIZE (Exa-Networks-exabgp-4.2.13_GH0.tar.gz) = 2932003

net/exabgp4/files/patch-lib_exabgp_reactor_network_outgoing.py

@@ -1,11 +0,0 @@
---- lib/exabgp/reactor/network/outgoing.py.orig	2021-06-02 13:31:16 UTC
-+++ lib/exabgp/reactor/network/outgoing.py
-@@ -53,6 +53,8 @@ class Outgoing(Connection):
-             connect(self.io, self.peer, self.port, self.afi, self.md5)
-             return None
-         except NetworkError as exc:
-+            self.io.close()
-+            self.io = None
-             return exc
- 
-     def establish(self):