drop cosign.pub steps, the pubkey is in the git repo root

Author: vszakats

.github/workflows/build_latest_release_multi.yml

@@ -82,10 +82,6 @@ jobs:
           cosign sign -y --key cosign.key ghcr.io/curl/curl-container/curl-base-multi:$REL
         env:
           COSIGN_PASSWORD: ${{secrets.COSIGN_PASSWORD}}
-      - name: Write public key to disk
-        env:
-          COSIGN_PUBLIC_KEY: '${{ secrets.COSIGN_PUBLIC_KEY }}'
-        run: echo "${COSIGN_PUBLIC_KEY}" > cosign.pub
       - name: Verify image with public key
         run: |
           cosign verify --key cosign.pub ghcr.io/curl/curl-container/curl-multi:$REL

.github/workflows/build_master.yml

@@ -78,10 +78,6 @@ jobs:
           cosign sign -y --key cosign.key ghcr.io/curl/curl-container/curl:master
         env:
           COSIGN_PASSWORD: ${{secrets.COSIGN_PASSWORD}}
-      - name: Write public key to disk
-        env:
-          COSIGN_PUBLIC_KEY: '${{ secrets.COSIGN_PUBLIC_KEY }}'
-        run: echo "${COSIGN_PUBLIC_KEY}" > cosign.pub
       - name: Verify image with public key
         run: |
           cosign verify --key cosign.pub ghcr.io/curl/curl-container/curl-dev:master

.github/workflows/build_master_dev.yml

@@ -73,10 +73,6 @@ jobs:
           cosign sign -y --key cosign.key ghcr.io/curl/curl-container/curl-dev-debian:master
         env:
           COSIGN_PASSWORD: ${{secrets.COSIGN_PASSWORD}}
-      - name: Write public key to disk
-        env:
-          COSIGN_PUBLIC_KEY: '${{ secrets.COSIGN_PUBLIC_KEY }}'
-        run: echo "${COSIGN_PUBLIC_KEY}" > cosign.pub
       - name: Verify image with public key
         run: |
           cosign verify --key cosign.pub ghcr.io/curl/curl-container/curl-dev-debian:master

.github/workflows/build_master_multi.yml

@@ -76,10 +76,6 @@ jobs:
           cosign sign -y --key cosign.key ghcr.io/curl/curl-container/curl-base-multi:master
         env:
           COSIGN_PASSWORD: ${{secrets.COSIGN_PASSWORD}}
-      - name: Write public key to disk
-        env:
-          COSIGN_PUBLIC_KEY: '${{ secrets.COSIGN_PUBLIC_KEY }}'
-        run: echo "${COSIGN_PUBLIC_KEY}" > cosign.pub
       - name: Verify image with public key
         run: |
           cosign verify --key cosign.pub ghcr.io/curl/curl-container/curl-multi:master