Update change log with flexbox properties addition
Update change log with flexbox properties addition

chatzipan/scss-lint,gajus/scss-lint,philipgiuliani/scss-lint,cih/scss-lint,ingdir/scss-lint,bkeepers/scss-lint,dwayhs/scss-lint,gatero/scss-lint,teoljungberg/scss-lint,davecarter/scss-lint,baileyparker/scss-lint,leseulsteve/scss-lint