Merge pull request #441 from plotly/june-2026-webinar-ad

Change ad to June 2026 webinar

Author: red-patience

_includes/layouts/webinar_plug.html

@@ -1,5 +1,5 @@
 
-   <a href="https://plotly.com/webinars/plotly-studio-agentic/?utm_source=graphing_libraries&utm_medium=documentation&utm_campaign=plotly-studio-agentic-27may2026&utm_content=sidebar" target="_blank">
-     <img src="https://images.prismic.io/plotly-marketing-website-2/agI6_KYofJOwHGWJ_plotly-studio-agentic-docs.jpg?auto=format,compress"
-     style="width: 200px; height: 200px; position: fixed; bottom: 10px; left: 50px" alt="Sign up for the upcoming webinar: Plotly Studio Enters the Agentic Era">
+   <a href="https://plotly.com/webinars/dash-mcp-coding-agents/?utm_source=graphing_libraries&utm_medium=documentation&utm_campaign=dash-mcp-coding-agents-23june2026&utm_content=sidebar" target="_blank">
+     <img src="https://images.prismic.io/plotly-marketing-website-2/ahYL9bK9tuLqEKmz_dash-mcp-coding-agents.jpg?auto=format,compress"
+     style="width: 200px; height: 200px; position: fixed; bottom: 10px; left: 50px" alt="Sign up for the upcoming webinar: Introducing Dash MCP + Building Dash Apps with Coding Agents">
    </a>