appveyor.yml: upgrade to waf 1.8.22

diff --git a/appveyor.yml b/appveyor.yml
index c26fbac..a0ad7f8 100644 (file)
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -49,7 +49,7 @@ install:
   - "pip install --upgrade setuptools"
 
 before_build:
-  - curl -fsS -o waf https://waf.io/waf-1.8.20
+  - curl -fsS -o waf https://waf.io/waf-1.8.22
   - curl -fsS -o waf.bat https://raw.githubusercontent.com/waf-project/waf/master/utils/waf.bat
 
 build_script: