libpqxx: bump version, update pkg hash

Signed-off-by: Igor Bezzubchenko <garikello@gmail.com>

libs/libpqxx/Makefile

@@ -1,13 +1,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libpqxx
-PKG_VERSION:=7.3.0
+PKG_VERSION:=7.3.1
 PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=https://github.com/jtv/libpqxx
 PKG_SOURCE_VERSION:=$(PKG_VERSION)
-PKG_MIRROR_HASH:=c176771dbbf02e38b84a8f9bf986a83587e2d86d9e0d2238e2a17a036e865951
+PKG_MIRROR_HASH:=6d5b66f01285310a53815963d56f5137be2d05fe426b0e15d73cd8df92b84989
 
 CMAKE_INSTALL:=1