Fix issue links in README
Fix issue links in README

jgraichen/redmine_dashboard,intfrr/redmine_dashboard,jmfarina/redmine_dashboard,jgraichen/redmine_dashboard,intfrr/redmine_dashboard,jgraichen/redmine_dashboard,intfrr/redmine_dashboard,intfrr/redmine_dashboard,jmfarina/redmine_dashboard,jmfarina/redmine_dashboard,jmfarina/redmine_dashboard