Fire Proof Goliath Cloak (#74954)

## About The Pull Request
Right so, I was trying to imagine why goliath cloak isn't fire proof
when goliaths can quite literally bathe in lava. So I decided it must be
an oversight.
So now they're fireproof.

![image](https://user-images.githubusercontent.com/126404225/234091167-8018bf17-3f04-45e2-9b16-a15f765e1288.png)
## Why It's Good For The Game
Fireproof mob leather is actually fireproof
## Changelog
🆑

fix: fixed an oversight - Made Goliath Cloak and Goliath Cloak Hood
fireproof. And Goliath hide.
/🆑

code/game/objects/items/stacks/sheets/leather.dm

@@ -255,6 +255,7 @@ GLOBAL_LIST_INIT(sinew_recipes, list ( \
 	max_amount = 6
 	novariants = FALSE
 	item_flags = NOBLUDGEON
+	resistance_flags = FIRE_PROOF
 	w_class = WEIGHT_CLASS_NORMAL
 	layer = MOB_LAYER
 	merge_type = /obj/item/stack/sheet/animalhide/goliath_hide

code/modules/mining/equipment/explorer_gear.dm

@@ -126,6 +126,7 @@
 		/obj/item/spear,
 		/obj/item/tank/internals,
 		)
+	resistance_flags = FIRE_PROOF
 	armor_type = /datum/armor/cloak_goliath
 	hoodtype = /obj/item/clothing/head/hooded/cloakhood/goliath
 	body_parts_covered = CHEST|GROIN|ARMS
@@ -168,6 +169,7 @@
 	clothing_flags = SNUG_FIT
 	flags_inv = HIDEEARS|HIDEEYES|HIDEHAIR|HIDEFACIALHAIR
 	transparent_protection = HIDEMASK
+	resistance_flags = FIRE_PROOF
 
 /datum/armor/cloakhood_goliath
 	melee = 35