Changeset for prompt template node

This should have been included with the prompt template PR, but I'm still
learning how changesets work.

custom_nodes/.changeset/olive-windows-lie.md

@@ -0,0 +1,10 @@
+---
+'@visualblocks/devserver': minor
+'@visualblocks/custom-node-types': minor
+'@visualblocks/eslint-config': minor
+'@visualblocks/gemini': minor
+'@visualblocks/node-utils': minor
+'@visualblocks/tsconfig': minor
+---
+
+Add a prompt template node to @visualblocks/gemini