doc: add abubakar bio and picture to website (#75)

* doc: add abubakar's bio

_data/team.yml

@@ -73,6 +73,13 @@
   link: https://twitter.com/darosior
   image: assets/images/antoine.jpg
   alt: Picture of Antoine Poinsot
+- name: Abubakar Sadiq Ismail
+  title: Engineer
+  description: Abubakar is a software engineer from Nigeria. He holds a bachelor's degree in Computer Science and was introduced to Bitcoin open source development during the 2023 <a href="https://www.btrust.tech/builders" target="_blank">Btrust Builders</a> Fellowship. Since then, he has actively contributed to Bitcoin Core through pull requests and code reviews. Abubakar is particularly interested in Empirical Data Analysis, Fee Estimation, Mempool Policy, and Performance Optimization.
+  social: "@sadeeq_ismaela"
+  link: https://twitter.com/sadeeq_ismaela
+  image: assets/images/abubakar.jpg
+  alt: Picture of Abubakar
 - name: Gurwinder Sahota
   title: Operations Associate
   description: Passionate about creating safe and welcoming work and learning environments, Gurwinder is committed to supporting, streamlining, and optimizing Chaincode Labs' educational initiatives and operational objectives. She enjoys creating inclusive spaces where everyone feels comfortable and appreciated. Previously, Gurwinder worked as an Assistant Site Director at a local educational non-profit organization. In her free time, Gurwinder enjoys weightlifting, rollerblading, and hiking.