Fix edge case with early snapshot version detection (FabricMC#897)

Between 1.2 and the mid-1.7s, Mojang had a weird versioning system where pre-releases would 'reserve' a version number, and if additional pre-releases were required, the version number would be bumped. This led to some minor versions being 'skipped'.
This was not previously accounted for in the version detection for snapshots.
The snapshot 12w42b, for example, was followed by 1.4 pre-release, and 1.4.1 pre-release, before 1.4.2 became the first stable 1.4.x version. Previously, 12w42b would have been detected by Loader as a 1.4.2 snapshot - technically correct, but would have made its semver place it *after* 1.4 and 1.4.1, which is incorrect.
This PR fixes all such cases.

minecraft/src/main/java/net/fabricmc/loader/impl/game/minecraft/McVersionLookup.java

@@ -338,9 +338,9 @@ protected static String getRelease(String version) {
 			} else if (year == 14 && week >= 2 && week <= 34) {
 				return "1.8";
 			} else if (year == 13 && week >= 47 && week <= 49) {
-				return "1.7.4";
+				return "1.7.3";
 			} else if (year == 13 && week >= 36 && week <= 43) {
-				return "1.7.2";
+				return "1.7";
 			} else if (year == 13 && week >= 16 && week <= 26) {
 				return "1.6";
 			} else if (year == 13 && week >= 11 && week <= 12) {
@@ -350,11 +350,11 @@ protected static String getRelease(String version) {
 			} else if (year == 12 && week >= 49 && week <= 50) {
 				return "1.4.6";
 			} else if (year == 12 && week >= 32 && week <= 42) {
-				return "1.4.2";
+				return "1.4";
 			} else if (year == 12 && week >= 15 && week <= 30) {
-				return "1.3.1";
+				return "1.3";
 			} else if (year == 12 && week >= 3 && week <= 8) {
-				return "1.2.1";
+				return "1.2";
 			} else if (year == 11 && week >= 47 || year == 12 && week <= 1) {
 				return "1.1";
 			}