Merge bitcoin/bitcoin#28369: doc: Fill in the required skills in the good_first_issue template

fa3b816 doc: Fill in the required skills in the good_first_issue template (MarcoFalke)

Pull request description:

  Compiling and running the tests is always required, so fill it in to avoid having to type it manually every time.

ACKs for top commit:
  willcl-ark:
    ACK fa3b816

Tree-SHA512: 1bcb93aaff235dd62513cda05547db90d12ad7638c050ee125845d20df1e1bc457bf4ec590677a0875fae8729dcc58842398e637e517997b35e3b3adffc34a72

Author: fanquake

.github/ISSUE_TEMPLATE/good_first_issue.yml

@@ -29,8 +29,10 @@ body:
     attributes:
       label: Useful Skills
       description: For example, “`std::thread`”, “Qt5 GUI and async GUI design” or “basic understanding of Bitcoin mining and the Bitcoin Core RPC interface”.
-    validations:
-      required: false
+      value: |
+        * Compiling Bitcoin Core from source
+        * Running the C++ unit tests and the Python functional tests
+        * ...
   - type: textarea
     attributes:
       label: Guidance for new contributors