update hardcoded versions in preparation for the upcoming release. (#120)

Author: jothepro

README.md

@@ -68,7 +68,7 @@ Add the generator as a build requirement in `conanfile.txt`:
 
 ```text
 [build_requires]
-djinni-generator/1.2.0
+djinni-generator/1.3.0
 ```
 
 ## Credits

docs/setup.md

@@ -47,5 +47,5 @@ Add the generator as a build requirement in `conanfile.txt`:
 
 ```text
 [build_requires]
-djinni-generator/1.2.0
+djinni-generator/1.3.0
 ```