[vala-extra-vapis] glesv2: Fix glGetString()

[Rico Tzschichholz <ricotz src gnome org>]

commit 9a3e015c34da40e518f303bc80870312c03ca9d0
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Jul 2 18:59:57 2022 +0200

    glesv2: Fix glGetString()
    
    Fixes https://gitlab.gnome.org/GNOME/vala-extra-vapis/issues/10

 glesv2.vapi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/glesv2.vapi b/glesv2.vapi
index 6968760..bde7f76 100644
--- a/glesv2.vapi
+++ b/glesv2.vapi
@@ -596,7 +596,7 @@ namespace GLES2
     public void glGetShaderInfoLog (GLuint shader, GLsizei bufsize, GLsizei* length, GLchar* infolog);
     public void glGetShaderPrecisionFormat (GLenum shadertype, GLenum precisiontype, GLint* range, GLint* 
precision);
     public void glGetShaderSource (GLuint shader, GLsizei bufsize, GLsizei* length, GLchar* source);
-    public string glGetString (GLenum name);
+    public unowned string glGetString (GLenum name);
     public void glGetTexParameterfv (GLenum target, GLenum pname, GLfloat* params);
     public void glGetTexParameteriv (GLenum target, GLenum pname, GLint* params);
     public void glGetUniformfv (GLuint program, GLint location, GLfloat* params);