docs(readme): fix total downloads badge

The release downloads badge from shields.io only checks the first 100
most recent GitHub Releases to calculate the download totals. This
obviously yields invalid values if a repository has more than 100
releases.

Hence we're switching the badge to source it's data from a custom JSON
file in the meta branch, which is updated once an hour but a scheduled
GitHub Actions workflow which runs a Go file that checks all releases
from all pages for downloads counts.

README.md

@@ -28,7 +28,7 @@
     <img alt="GitHub pull requests" src="https://img.shields.io/github/issues-pr-raw/jimeh/emacs-builds?style=flat&logo=github&logoColor=white">
   </a>
   <a href="https://github.com/jimeh/emacs-builds/releases">
-    <img alt="GitHub all releases" src="https://img.shields.io/github/downloads/jimeh/emacs-builds/total?style=flat&logoColor=white&logo=data%3Aimage%2Fpng%3Bbase64,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%2FPnP7qIwAAAGBaUNDUHNSR0IgSUVDNjE5NjYtMi4xAAAokXWRzytEURTHP2aIGBEWFhaThtWM%2FKiJjTLSUJM0RhlsZp55M2rezOu9N2myVbaKEhu%2FFvwFbJW1UkRKdsqa2KDnPKNGMud27vnc773ndO%2B54IplFc2s7gUtZxnRcMg7G5%2Fz1j5SQwvQzEBCMfWRqakIFe3thionXgWcWpXP%2FWsNiylTgao64WFFNyzhceHIsqU7vCncpmQSi8LHwn5DLih87ejJEj85nC7xh8NGLDoKrmZhb%2FoXJ3%2BxkjE0YXk5Pi1bUH7u47zEk8rNTEvsFO%2FAJEqYEF4mGGOUIH0MyRwkQD89sqJCfu93%2FiR5yVVk1ilisESaDBZ%2BUQtSPSVRFT0lI0vR6f%2FfvprqQH%2BpuicENQ%2B2%2FdIFtRvwuW7b7%2Fu2%2FXkA7ns4y5Xz83sw%2BCr6elnz7ULTKpycl7XkFpyuQfudnjAS35Jb3KWq8HwEjXFovYT6%2BVLPfvY5vIXYinzVBWzvQLecb1r4AjtZZ9JRQIRfAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAhUlEQVQokb3QsQnDMBRF0Y9J6QGylCt7GI%2BRPdJ4BIMXyA4pM0KKk0YCYawogZAHH4Tuvw%2BhiEowY67xarBirfHu68afijjXFvesK8AQEXeMB9KU2HDU2GPDE2P%2BHEzpbkNfe04pP9K8lw7knLa0k69pPpP%2BFyzaWfL%2BqXAvEXFr9K%2F58AJFIbDLRt48DAAAAABJRU5ErkJggg%3D%3D&color=blue&label=total%20downloads">
+    <img alt="GitHub all releases" src="https://img.shields.io/endpoint?url=https%3A%2F%2Fraw.githubusercontent.com%2Fjimeh%2Femacs-builds%2Fmeta%2Ftotal-downloads%2Fshield.json">
   </a>
 </p>