Updated SageMath version to 8.5.beta4

VERSION.txt

-SageMath version 8.5.beta3, Release Date: 2018-11-11
+SageMath version 8.5.beta4, Release Date: 2018-11-18

build/pkgs/configure/checksums.ini

 tarball=configure-VERSION.tar.gz
-sha1=0ed00ab9925291f76228582bfb16e211b20d49ae
-md5=0e58299d30d067ccea3e75561d0eaaf8
-cksum=2356004790
+sha1=0a8ccb51309ccd09f7290238fb529cab7ca591b2
+md5=c4b07abb7ea9f7064a5981539e9e9543
+cksum=36612397

build/pkgs/configure/package-version.txt

-291
+292

src/bin/sage-version.sh

 # Sage version information for shell scripts
 # This file is auto-generated by the sage-update-version script, do not edit!
-SAGE_VERSION='8.5.beta3'
-SAGE_RELEASE_DATE='2018-11-11'
-SAGE_VERSION_BANNER='SageMath version 8.5.beta3, Release Date: 2018-11-11'
+SAGE_VERSION='8.5.beta4'
+SAGE_RELEASE_DATE='2018-11-18'
+SAGE_VERSION_BANNER='SageMath version 8.5.beta4, Release Date: 2018-11-18'

src/sage/version.py

 # Sage version information for Python scripts
 # This file is auto-generated by the sage-update-version script, do not edit!
-version = '8.5.beta3'
-date = '2018-11-11'
-banner = 'SageMath version 8.5.beta3, Release Date: 2018-11-11'
+version = '8.5.beta4'
+date = '2018-11-18'
+banner = 'SageMath version 8.5.beta4, Release Date: 2018-11-18'