Use splitScalar for splitting

Zig master has officially deprecated `std.mem.split`, so this will keep
the library compatible going forward.

README.md

@@ -15,7 +15,7 @@ Let me show you its features!
 The best way to use `ohsnap` is to install it using the [Zig Build System](https://ziglang.org/learn/build-system/).  From your project repo root, use `zig fetch` like this:
 
 ```sh
-zig fetch --save "https://github.com/mnemnion/ohsnap/archive/refs/tags/v0.1.1.tar.gz"
+zig fetch --save "https://github.com/mnemnion/ohsnap/archive/refs/tags/v0.1.2.tar.gz"
 ```
 
 Then add it to your test artifact like so:
@@ -152,7 +152,7 @@ Simply replace the timestamp like so:
         \\ohsnap.StampedStruct
         \\  .message: []const u8
         \\    "frobnicate the turbo-encabulator"
-        \\  .tag: u64 = 17337
+        \\  .tag: u64 = 37337
         \\  .timestamp: isize = <^\d+$>
         ,
     ).expectEqual(with_stamp);
@@ -167,7 +167,7 @@ Let's say you make a change:
 ```zig
     const with_stamp = StampedStruct.init(
         "thoroughly frobnicate the encabulator",
-        17337,
+        37337,
     );
 ```
 
@@ -182,7 +182,7 @@ Since this was an intentional change, we need to update the snap:
         \\ohsnap.StampedStruct
         \\  .message: []const u8
         \\    "frobnicate the turbo-encabulator"
-        \\  .tag: u64 = 17337
+        \\  .tag: u64 = 37337
         \\  .timestamp: isize = <^\d+$>
         ,
     ).expectEqual(with_stamp);
@@ -196,7 +196,7 @@ Once again, through the magic of diffing, `ohsnap` will locate the regexen in th
         \\ohsnap.StampedStruct
         \\  .message: []const u8
         \\    "thoroughly frobnicate the encabulator"
-        \\  .tag: u64 = 17337
+        \\  .tag: u64 = 37337
         \\  .timestamp: isize = <^\d+$>
         ,
     ).expectEqual(with_stamp);

src/ohsnap.zig

@@ -180,7 +180,7 @@ pub const Snap = struct {
 
         try file_text_updated.appendSlice(snapshot_prefix);
         {
-            var lines = std.mem.split(u8, got, "\n");
+            var lines = std.mem.splitScalar(u8, got, '\n');
             while (lines.next()) |line| {
                 try file_text_updated.writer().print("{s}\\\\{s}\n", .{ indent, line });
             }
@@ -377,7 +377,7 @@ fn snapRange(text: []const u8, src_line: u32) !Range {
     var offset: usize = 0;
     var line_number: u32 = 0;
 
-    var lines = std.mem.split(u8, text, "\n");
+    var lines = std.mem.splitScalar(u8, text, '\n');
     const snap_start = while (lines.next()) |line| : (line_number += 1) {
         if (line_number == src_line) {
             if (std.mem.indexOf(u8, line, "@src()") == null) {
@@ -401,7 +401,7 @@ fn snapRange(text: []const u8, src_line: u32) !Range {
         offset += line.len + 1; // 1 for \n
     } else unreachable;
 
-    lines = std.mem.split(u8, text[snap_start..], "\n");
+    lines = std.mem.splitScalar(u8, text[snap_start..], '\n');
     const snap_end = while (lines.next()) |line| {
         if (!isMultilineString(line)) {
             break offset;