Move YARN-3790 from 2.7.1 to 2.8 in CHANGES.txt
Move YARN-3790 from 2.7.1 to 2.8 in CHANGES.txt

zrccxyb62/hadoop,Microsoft-CISL/hadoop-prototype,zrccxyb62/hadoop,Microsoft-CISL/hadoop-prototype,Microsoft-CISL/hadoop-prototype,satishpatil2k13/ODPI-Hadoop,intel-hadoop/hadoop,intel-hadoop/hadoop,intel-hadoop/hadoop,MjAbuz/hadoop,intel-hadoop/hadoop,zrccxyb62/hadoop,MjAbuz/hadoop,zrccxyb62/hadoop,satishpatil2k13/ODPI-Hadoop,Microsoft-CISL/hadoop-prototype,MjAbuz/hadoop,MjAbuz/hadoop,zrccxyb62/hadoop,zrccxyb62/hadoop,satishpatil2k13/ODPI-Hadoop,intel-hadoop/hadoop,satishpatil2k13/ODPI-Hadoop,zrccxyb62/hadoop,Microsoft-CISL/hadoop-prototype,MjAbuz/hadoop,satishpatil2k13/ODPI-Hadoop,satishpatil2k13/ODPI-Hadoop,intel-hadoop/hadoop,Microsoft-CISL/hadoop-prototype,satishpatil2k13/ODPI-Hadoop,Microsoft-CISL/hadoop-prototype,Microsoft-CISL/hadoop-prototype,intel-hadoop/hadoop,MjAbuz/hadoop,MjAbuz/hadoop,satishpatil2k13/ODPI-Hadoop