patch 8.2.3022: available encryption methods are not strong enough

Problem:    Available encryption methods are not strong enough.
Solution:   Add initial support for xchaha20. (Christian Brabandt,
            closes #8394)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 97f7b61..9267117 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -5072,6 +5072,13 @@
 		0
 #endif
 		},
+	{"sodium",
+#ifdef FEAT_SODIUM
+		1
+#else
+		0
+#endif
+		},
 	{"sound",
 #ifdef FEAT_SOUND
 		1