update po4a installation script to v0.74

This version of po4a includes several bug fixes and improvements for
better handling of asciidoc files.

Signed-off-by: Jean-Noël Avila <[email protected]>

Author: jnavila

ci/install_po4a.sh

@@ -1,4 +1,4 @@
 #!/bin/sh
 
 git clone https://github.com/mquinson/po4a.git
-cd po4a && git checkout v0.72 && cd ..
+cd po4a && git checkout v0.74 && cd ..