ci(build): fix inconsistent builds

we were building from the current state of master whenever the job ran,
which is incorrect. it should've checked the exact tag out before building. this commit fixes that

it also adds a simple regex to filter out other releases(e.g.: for android)

.github/workflows/build.yml

@@ -5,8 +5,9 @@ on:
     branches:
       - trunk
   schedule:
-    - cron: '0 22 1/2 * *' # every other day at midnight
+    - cron: '0 16 * * 5' # what could go wrong on a friday evening ¯\_ (ツ)_/¯
   workflow_dispatch:
+
 env:
   LUANTI_REPO: minetest/minetest
   LUANTI_DIR: luanti
@@ -62,13 +63,18 @@ jobs:
           echo "Current version: ${CURRENT_VERSION}"
           echo "Latest version: ${LATEST_VERSION}"
 
-          if [ "$LATEST_VERSION" != "$CURRENT_VERSION" ]; then
-            echo "New release found: ${LATEST_VERSION}"
-            echo "SHOULD_BUILD=true" >> $GITHUB_OUTPUT
-            echo "LATEST_VERSION=${LATEST_VERSION}" >> $GITHUB_OUTPUT
-            echo "CURRENT_VERSION=${CURRENT_VERSION}" >> $GITHUB_OUTPUT
+          if [[ "$LATEST_VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+            if [ "$LATEST_VERSION" != "$CURRENT_VERSION" ]; then
+              echo "Will make a build"
+              echo "SHOULD_BUILD=true" >> $GITHUB_OUTPUT
+              echo "LATEST_VERSION=${LATEST_VERSION}" >> $GITHUB_OUTPUT
+              echo "CURRENT_VERSION=${CURRENT_VERSION}" >> $GITHUB_OUTPUT
+            else
+              echo "No new release found."
+              echo "SHOULD_BUILD=false" >> $GITHUB_OUTPUT
+            fi
           else
-            echo "No new release found."
+            echo "Latest version is not a semantic version, skipping build."
             echo "SHOULD_BUILD=false" >> $GITHUB_OUTPUT
           fi
 
@@ -91,6 +97,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: ${{ env.LUANTI_REPO }}
+          ref: ${{ env.LATEST_VERSION }}
           path: ${{ env.LUANTI_DIR }}
 
       - name: Install system dependencies
@@ -100,15 +107,13 @@ jobs:
           sudo apt-get install -y ${{ env.DEPENDENCIES }}
 
       - name: Download appimage-builder
-        if: steps.cache-tools-restore.outputs.cache-hit != 'true'
         run: |
           mkdir -p ${{ env.TOOLS_DIR }}
           cd ${{ env.TOOLS_DIR }}
           wget -O appimage-builder.AppImage https://github.com/AppImageCrafters/appimage-builder/releases/download/v1.1.0/appimage-builder-1.1.0-x86_64.AppImage
           chmod +x appimage-builder.AppImage
 
       - name: Build Luanti
-        if: steps.cache-minetest-restore.outputs.cache-hit != 'true'
         run: |
           set -e
           cd ${{ env.LUANTI_DIR }}