package/waf: bump to version 2.0.20

Also switch to the new 2 spaces convention for the hash file

Signed-off-by: Titouan Christophe <titouan.christophe@railnova.eu>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/waf/waf.hash

@@ -1,3 +1,3 @@
 # Locally computed
-sha1    d857c29d49848e0fc42e69daa25e0ec2e732ac17                          waf-2.0.19
-sha256  ba63c90a865a9bcf46926c4e6776f9a3f73d29f33d49b7f61f96bc37b7397cef  waf-2.0.19
+sha1  92212071a63ce38fdfd69fb8332f04e84d1f6635  waf-2.0.20
+sha256  bf971e98edc2414968a262c6aa6b88541a26c3cd248689c89f4c57370955ee7f  waf-2.0.20

package/waf/waf.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-WAF_VERSION = 2.0.19
+WAF_VERSION = 2.0.20
 WAF_SOURCE = waf-$(WAF_VERSION)
 WAF_SITE = https://waf.io