fix: record sqlite3 version even on failure to keep python cache

If SQLite3 apt install fails, still write python-sqlite3-version so
steps/python doesn't clear the python cache and re-download the runtime
on every build. Avoids repeated full re-downloads + builds.

bin/steps/sqlite3

@@ -82,12 +82,15 @@ buildpack_sqlite3_install() {
     if [ "$INSTALLED_SQLITE3_VERSION" != "$SQLITE3_VERSION" ]; then
       puts-step "Installing SQLite3"
       if sqlite3_install "$BUILD_DIR/.heroku/python" "$SQLITE3_VERSION"; then
-        # save version installed
-        mkdir -p "$CACHE_DIR/.heroku/"
-        echo "$SQLITE3_VERSION" > "$CACHE_DIR/.heroku/python-sqlite3-version"
+        puts-step "SQLite3 installed"
       else
         puts-warn "SQLite3 install failed (EOL apt repos?), continuing without it"
       fi
+
+      # Record the version even on failure so the python cache isn't cleared
+      # and the runtime isn't re-downloaded on every subsequent build.
+      mkdir -p "$CACHE_DIR/.heroku/"
+      echo "$SQLITE3_VERSION" > "$CACHE_DIR/.heroku/python-sqlite3-version"
     fi
   fi
 }