Update maintainers (#15)

Author: christophfroehlich

tcb_span/package.xml

@@ -4,9 +4,11 @@
   <name>tcb_span</name>
   <version>1.2.0</version>
   <description>Implementation of C++20's std::span</description>
-  <maintainer email="maybe@tylerjw.dev">Tyler Weaver</maintainer>
+  <maintainer email="bence.magyar.robotics@gmail.com">bmagyar</maintainer>
+  <maintainer email="christoph.froehlich@ait.ac.at">christophfroehlich</maintainer>
   <maintainer email="nathanbrooks@picknik.ai">Nathan Brooks</maintainer>
   <maintainer email="shaurya.kumar@picknik.ai">Shaurya Kumar</maintainer>
+  <author email="maybe@tylerjw.dev">Tyler Weaver</author>
 
   <license>BSL-1.0</license>
   <url>https://github.com/tcbrindle/span</url>

tl_expected/package.xml

@@ -4,11 +4,13 @@
   <name>tl_expected</name>
   <version>1.2.0</version>
   <description>C++11/14/17 std::expected with functional-style extensions</description>
-  <maintainer email="maybe@tylerjw.dev">Tyler Weaver</maintainer>
+  <maintainer email="bence.magyar.robotics@gmail.com">bmagyar</maintainer>
+  <maintainer email="christoph.froehlich@ait.ac.at">christophfroehlich</maintainer>
   <maintainer email="nathanbrooks@picknik.ai">Nathan Brooks</maintainer>
   <maintainer email="shaurya.kumar@picknik.ai">Shaurya Kumar</maintainer>
 
   <author>Sy Brand</author>
+  <author email="maybe@tylerjw.dev">Tyler Weaver</author>
   <license>CC0-1.0</license>
   <url>https://github.com/TartanLlama/expected</url>