Decrease memory usage in ARMv7 CI

Our GitHub Actions CI was failing because the ARMv7 systems use QEMU
which consumes more memory than usual, by decreasing the memory usage,
we expect to make it all work again.

tests/integration.rs

@@ -108,7 +108,11 @@ fn single_empty_file(ext: Extension, #[any(size_range(0..8).lift())] exts: Vec<F
 fn single_file(
     ext: Extension,
     #[any(size_range(0..8).lift())] exts: Vec<FileExtension>,
-    #[strategy(proptest::option::of(0i16..12))] level: Option<i16>,
+    #[cfg_attr(not(target_arch = "arm"), strategy(proptest::option::of(0i16..12)))]
+    // Decrease the value of --level flag for `arm` systems, because our GitHub
+    // Actions CI runs QEMU which makes the memory consumption higher.
+    #[cfg_attr(target_arch = "arm", strategy(proptest::option::of(0i16..8)))]
+    level: Option<i16>,
 ) {
     let dir = tempdir().unwrap();
     let dir = dir.path();