Adjust logo light-dark mode in README.md (#3739)

README.md

@@ -1,4 +1,9 @@
-![JuMP logo](https://jump.dev/JuMP.jl/dev/assets/logo-with-text-background.svg "JuMP logo")
+<picture>
+  <source media="(prefers-color-scheme: light)" srcset="https://jump.dev/JuMP.jl/dev/assets/logo-with-text.svg">
+  <source media="(prefers-color-scheme: dark)" srcset="https://jump.dev/JuMP.jl/dev/assets/logo-dark-with-text.svg">
+  <img alt="JuMP.jl logo." src="https://jump.dev/JuMP.jl/dev/assets/logo-with-text-background.svg">
+</picture>
+
 ---
 
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