adapt gcovr 8.6

Author: fchn289

ut/gcovr/gcovr.cfg

@@ -10,7 +10,7 @@ exclude-throw-branches       = yes  # inc coverage
 exclude-noncode-lines        = yes  # 6.0
 exclude-lines-by-pattern     = ^(\s)*\b(DBG|INF|WRN|ERR|HID)\b\(.*$
 
-fail-under-line   = 88.1  # since gcovr8.4 bugs
+fail-under-line   = 87.4  # since gcovr8.6
 fail-under-branch = 73.2  # since gcovr8.4 bugs
 
 html          = yes  # summary report