docs: updated readme

README.md

@@ -128,6 +128,7 @@ greater than or equal to 4.2.3.
 The basic comparisons are:
 
 * `=`: equal (aliased to no operator)
+* `==`: strictly equal
 * `!=`: not equal
 * `>`: greater than
 * `<`: less than
@@ -181,6 +182,7 @@ for all comparison operators. When used on the `=` operator it falls
 back to the patch level comparison (see tilde below). For example,
 
 * `1.2.x` is equivalent to `>= 1.2.0, < 1.3.0`
+* `==1.2.x` is equivalent to `== 1.2.0`
 * `>= 1.2.x` is equivalent to `>= 1.2.0`
 * `<= 2.x` is equivalent to `< 3`
 * `*` is equivalent to `>= 0.0.0`