Use liv2/amiga-gcc container for release / coverity

This is to ensure we stick with GCC 6.5

.github/workflows/coverity.yml

@@ -10,7 +10,7 @@ on:
 jobs:
   coverity:
     runs-on: ubuntu-latest
-    container: stefanreinauer/amiga-gcc
+    container: liv2/amiga-gcc
     steps:
     - uses: actions/checkout@v3
       with:

.github/workflows/release.yml

@@ -12,7 +12,7 @@ on:
 jobs:
   make_software:
     runs-on: ubuntu-latest
-    container: liv2/amiga-gcc-amitools
+    container: liv2/amiga-gcc
     steps:
       - name: Checkout
         uses: actions/checkout@v3

README.md

@@ -123,7 +123,7 @@ Building this code will require the following
 The easiest way to get a working build environment is to use Docker
 You can build inside docker as follows:
 ```  
-docker run --rm -it -v ${PWD}:${PWD} -w ${PWD} stefanreinauer/amiga-gcc:latest make clean all
+docker run --rm -it -v ${PWD}:${PWD} -w ${PWD} liv2/amiga-gcc:latest make clean all
 ```
 
 If you are using VS Code you can install the "Dev containers" extension which will allow you to develop with the environment ready to go.