Fix pk_len() for BareCtx

The `pk_len()` returned should account for the extra byte for the
OP_PUSH opcode. This is true for all the other contexts, but not for
`BareCtx`, so this commit fixes it.

Author: afilini

src/miniscript/context.rs

@@ -739,9 +739,9 @@ impl ScriptContext for BareCtx {
 
     fn pk_len<Pk: MiniscriptKey>(pk: &Pk) -> usize {
         if pk.is_uncompressed() {
-            65
+            66
         } else {
-            33
+            34
         }
     }