Merge #472: Fix pk_len() for BareCtx

f3ae0d8 Fix `pk_len()` for `BareCtx` (Alekos Filini)

Pull request description:

  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.

  ------

  This PR is based on the `7.0.0` tag because in my opinion it's worth applying this and releasing as `7.0.1` without waiting for `8.0.0` (BDK would naturally benefit from this because we are about to make one new release still based on `7.0.0` and it's tricky to workaround this issue in our code).

  I think the patch is small enough that it can easily be applied on older releases as well, if you want to backport it too.

ACKs for top commit:
  evanlinjin:
    ACK f3ae0d8
  sanket1729:
    ACK f3ae0d8
  apoelstra:
    ACK f3ae0d8

Tree-SHA512: cc01c3a14708e081592b0a01d61ab7800ff5175047ef0b7315f56c898d84119270e5f680bb0de1d0997b4108be02af7d5896bab7c8cef8f053c99c979db9bf8b

Author: apoelstra

src/miniscript/context.rs

@@ -768,9 +768,9 @@ impl ScriptContext for BareCtx {
 
     fn pk_len<Pk: MiniscriptKey>(pk: &Pk) -> usize {
         if pk.is_uncompressed() {
-            65
+            66
         } else {
-            33
+            34
         }
     }