Installation step for GHC 8.8.3 added in README and stack.yaml modified to mirror stack-8.8.3.yaml

Author: iamsims

README.md

@@ -48,14 +48,20 @@ cd haskell-code-explorer
 
 To build Haskell Code Explorer Stack ([https://docs.haskellstack.org/en/stable/README/](https://docs.haskellstack.org/en/stable/README/)) is needed.
 
-At the moment Haskell Code Explorer supports GHC 8.6.5, 8.6.4, GHC 8.6.3, GHC 8.4.4, GHC 8.4.3, GHC 8.2.2, and 8.0.2.
+At the moment Haskell Code Explorer supports GHC 8.8.3, GHC 8.6.5, 8.6.4, GHC 8.6.3, GHC 8.4.4, GHC 8.4.3, GHC 8.2.2, and 8.0.2.
 
-For GHC 8.6.5:
+For GHC 8.8.3:
 
 ```bash
 stack install
 ```
 
+For GHC 8.6.5:
+
+```bash
+stack --stack-yaml=stack-8.6.4.yaml install
+```
+
 For GHC 8.6.4:
 
 ```bash

stack.yaml

@@ -1,7 +1,12 @@
-resolver: lts-14.1
+resolver: lts-15.4
 packages:
 - '.'
 - 'vendor/cabal-helper-0.8.1.2'
 allow-newer: true
 extra-deps:
-  - cabal-plan-0.4.0.0
+  - haddock-library-1.7.0@sha256:8f230ebb680b559256d9c18ce4942ba5bf220b167804b4ebd5cc9e47cc4973cd
+  - cabal-install-3.0.0.0@sha256:5e3c4376e53c06521cca2c037074423dbb967e228af6174bf842ff38aa82b035
+  - git: https://github.com/haskell/hackage-security
+    commit: 2057cdf2abba852881cd9d055c96f03cd8c829e7
+    subdirs:
+      - hackage-security