🌀 Add Bigint as a primitive type

[MDN](https://developer.mozilla.org/en-US/docs/Glossary/Primitive) considers `Bigint` as a primitive type.

02_Day_Data_types/02_day_data_types.md

@@ -57,12 +57,13 @@ In the previous section, we mentioned a little bit about data types. Data or val
 
 Primitive data types in JavaScript include:
 
- 1. Numbers - Integers, floats
- 2. Strings - Any data under single quote, double quote or backtick quote
- 3. Booleans - true or false value
+ 1. Number - Integers, floats
+ 2. String - Any data under single quote, double quote or backtick quote
+ 3. Boolean - true or false value
  4. Null - empty value or no value
  5. Undefined - a declared variable without a value
  6. Symbol - A unique value that can be generated by Symbol constructor
+ 7. Bigint - Is a numeric primitive in JavaScript that can represent integers with arbitrary magnitude
 
 Non-primitive data types in JavaScript includes: