patch 9.0.0267: Coverity workflow still uses Ubuntu 18.04

Problem:    Coverity workflow still uses Ubuntu 18.04.
Solution:   Use Ubuntu 20.04
diff --git a/.github/workflows/coverity.yml b/.github/workflows/coverity.yml
index a58a20b..566ab5b 100644
--- a/.github/workflows/coverity.yml
+++ b/.github/workflows/coverity.yml
@@ -6,7 +6,7 @@
 
 jobs:
   scan:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
 
     env:
       CC: gcc
diff --git a/src/version.c b/src/version.c
index 50294f8..b5cdfdf 100644
--- a/src/version.c
+++ b/src/version.c
@@ -728,6 +728,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    267,
+/**/
     266,
 /**/
     265,