docs(public_reference): add Flyweight as a public reference (aws-powertools#5322)

Adding Flyweight as public ref

Author: leandrodamascena

README.md

@@ -63,6 +63,7 @@ The following companies, among others, use Powertools:
 * [CPQi (Exadel Financial Services)](https://cpqi.com/)
 * [CloudZero](https://www.cloudzero.com/)
 * [CyberArk](https://www.cyberark.com/)
+* [Flyweight](https://flyweight.io/)
 * [globaldatanet](https://globaldatanet.com/)
 * [IMS](https://ims.tech/)
 * [Jit Security](https://www.jit.io/)

docs/index.md

@@ -448,6 +448,9 @@ Knowing which companies are using this library is important to help prioritize t
 [**CyberArk**](https://www.cyberark.com/){target="_blank" rel="nofollow"}
 { .card }
 
+[**Flyweight**](https://flyweight.io/){target="_blank" rel="nofollow"}
+{ .card }
+
 [**globaldatanet**](https://globaldatanet.com/){target="_blank" rel="nofollow"}
 { .card }