Air release post (#725)

* First draft of Air release post

* Refine refine refine

* Call out project specific settings option

* Incorporate feedback

* Explicitly mention GitHub Actions

* Mention projects we already use Air in

* Final tweaks

Author: DavisVaughan

content/blog/air/index.Rmd

@@ -0,0 +1,13 @@
+# Some beautiful ggplot2 code
+mpg |>
+  ggplot(aes(displ, hwy)) +
+  geom_point() +
+  geom_line(
+    data = grid,
+    colour = "blue",
+    linewidth = 1.5
+  ) +
+  geom_text(
+    data = outlier,
+    aes(label = model)
+  )