Merge #179: Update outdated GPG key verification details in documentation

9f4a4ce Update outdated GPG key verification details in documentation (Marco)

Pull request description:

  The GPG verification instructions in [Installing Elements](https://elementsproject.org/elements-code-tutorial/installing-elements) tutorial were outdated. The guide was still referencing Steven Roose's key, while recent releases are now signed by Pablo Greco.

  This PR updates the tutorial with the correct key ID and updates the example output to reflect the current signing process.

  Fixes #178

ACKs for top commit:
  delta1:
    ACK 9f4a4ce; verified psgreco GPG key details are correct

Tree-SHA512: d8416ed04f3c7161a935f8442734606a4b058680a4fd8f2e6e5659cfc3c608358b5bd757248defa2ca7de56dde913f707471cfe82a47f43b20775a485a27966d

Author: delta1

elements-code-tutorial/installing-elements.md

@@ -39,19 +39,19 @@ sha256sum: WARNING: 19 lines are improperly formatted
 You can verify the gpg signature of the hashes as follows:
 
 ```
-$ gpg --keyserver keyserver.ubuntu.com --recv-keys DE10E82629A8CAD55B700B972F2A88D7F8D68E87
-gpg: key 2A57E0A610D7F19C: public key "Steven Roose <steven@stevenroose.org>" imported
+$ gpg --keyserver keyserver.ubuntu.com --recv-keys BD0F3062F87842410B06A0432F656B0610604482
+gpg: key 2F656B0610604482: public key "Pablo Greco <pgreco@blockstream.com>" imported
 gpg: Total number processed: 1
 gpg:               imported: 1
+
 $ gpg --verify SHA256SUMS.asc 
-gpg: Signature made Thu 03 Mar 2022 06:02:41 AM PST
-gpg:                using RSA key DE10E82629A8CAD55B700B972F2A88D7F8D68E87
-gpg: Good signature from "Steven Roose <steven@stevenroose.org>" [unknown]
-gpg:                 aka "Steven Roose (Jabber) <steven@konuro.net>" [unknown]
+gpg: Signature made Mon 13 Apr 2026 06:06:31 PM CEST
+gpg:                using RSA key BD0F3062F87842410B06A0432F656B0610604482
+gpg: Good signature from "Pablo Greco <pgreco@blockstream.com>" [unknown]
+gpg:                 aka "Pablo Greco <psgreco@gmail.com>" [unknown]
 gpg: WARNING: This key is not certified with a trusted signature!
 gpg:          There is no indication that the signature belongs to the owner.
-Primary key fingerprint: 8CC9 74D9 CFD0 34DC EED2  13B0 2A57 E0A6 10D7 F19C
-     Subkey fingerprint: DE10 E826 29A8 CAD5 5B70  0B97 2F2A 88D7 F8D6 8E87
+Primary key fingerprint: BD0F 3062 F878 4241 0B06  A043 2F65 6B06 1060 4482
 ```
 
 Extract the archive, and copy the `elementsd`, `elements-cli`, and `elements-qt` executables to `/usr/local/bin`.