Bump auxil/spicy to latest development snapshot

This patch bump Spicy to the latest development snapshot. This
introduces a backwards-incompatible change in that it removes support
for a never officially supported syntax to specify unit fields (so I
would argue: not strictly a breaking change).

src/analyzer/protocol/finger/finger.spicy

@@ -15,7 +15,7 @@ public type Request  = unit {
 
     switch {
         -> : /\/W/ { self.whois = True; }
-        -> void;
+        -> : void;
     };
 
     : OptionalWhiteSpace;

src/analyzer/protocol/syslog/syslog.spicy

@@ -7,7 +7,7 @@ import spicy;
 public type Message = unit {
     switch {
         -> prio: Priority;
-        -> void;
+        -> : void;
     };
 
     msg: bytes &eod;