process: Proposed ↦ Complete

Amend CI script to new statuses and update existing status field values
in table and BIPs.

```
sed -z -i 's/Status: Proposed/Status: Complete/' bip-0*.md
sed -z -i 's/Status: Proposed/Status: Complete/' bip-0*.mediawiki
sed -i 's/| Proposed/| Complete/' README.mediawiki
```

bip-0388.mediawiki

@@ -5,7 +5,7 @@
   Author: Salvatore Ingala <salvatoshi@protonmail.com>
   Comments-Summary: No comments yet.
   Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0388
-  Status: Proposed
+  Status: Complete
   Type: Standards Track
   Created: 2022-11-16
   License: BSD-2-Clause