chore: update branding

[mdelapenya]

What is this PR doing?

It mimics what the Java folks are doing in testcontainers/testcontainers-java#5258

Why is it important?

Please read https://www.atomicjar.com/2022/04/new-milestone-new-look-new-release-same-testcontainers/ :)

Related issues

• Closes Update static assets for the new look& feel #428
• Relates Update Testcontainers branding testcontainers-java#5258

[codecov]

Codecov Report

Merging #429 (afe2deb) into main (976da32) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #429   +/-   ##
=======================================
  Coverage   65.28%   65.28%           
=======================================
  Files          19       19           
  Lines        1178     1178           
=======================================
  Hits          769      769           
- Misses        302      303    +1     
+ Partials      107      106    -1     

Impacted Files	Coverage Δ
docker.go	65.62% <0.00%> (ø)

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[bsideup]

👍