chore(constants): applies diffs from Jesse's subgraph PR

Source: Jesse-Sawa#1

I'm applying all changes made in this PR "v3-subgraph for celo changes
Uniswap#1" (Jesse-Sawa#1).

In this commit, I had to modify the original diff from Jesse a little, because the source code has changed slightly since he made the change.

src/mappings/position-manager.ts

@@ -162,11 +162,13 @@ export function handleCollect(event: Collect): void {
   }
 
   let token0 = Token.load(position.token0)
+  let token1 = Token.load(position.token1)
 
-  if (token0) {
+  if (token0 && token1) {
     let amount0 = convertTokenToDecimal(event.params.amount0, token0.decimals)
+    let amount1 = convertTokenToDecimal(event.params.amount1, token1.decimals)
     position.collectedFeesToken0 = position.collectedFeesToken0.plus(amount0)
-    position.collectedFeesToken1 = position.collectedFeesToken1.plus(amount0)
+    position.collectedFeesToken1 = position.collectedFeesToken1.plus(amount1)
   }
 
   position = updateFeeVars(position, event, event.params.tokenId)