Replace logo.png by logo.svg (#330)

# Pull Request

Replace the logo.png by logo.svg to reduce much more than the previous
compressions of png on #329: (500Kb -> 70Kb) and it is vectorized to
allow for any resolution.

Fixes insightsengineering/nestdevs-tasks#93

Author: llrs-roche

README.md

@@ -1,4 +1,4 @@
-# formatters <a href='https://github.com/insightsengineering/formatters'><img src="man/figures/logo.png" align="right" alt="" width="180"></a>
+# formatters <a href='https://github.com/insightsengineering/formatters'><img src="man/figures/logo.svg" align="right" alt="" width="180"></a>
 
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