Minor fix to support Zig 0.13

Author: deckarep

.gitignore

@@ -1,2 +1,3 @@
+.zig-cache
 /zig-cache
-/zig-out
+/zig-out

build.zig

@@ -7,14 +7,14 @@ pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
 
     _ = b.addModule("ziglangSet", .{
-        .root_source_file = .{ .path = "src/root.zig" },
+        .root_source_file = b.path("src/root.zig"),
         .target = target,
         .optimize = optimize,
     });
 
     const main_tests = b.addTest(.{
         .name = "ziglang-set tests",
-        .root_source_file = .{ .path = "src/root.zig" },
+        .root_source_file = b.path("src/root.zig"),
         .target = target,
         .optimize = optimize,
     });