ci: Switch to new Linux docker image

Switch to the new Linux docker image with Vulkan headers from
scp-fs2open/docker-images#7, for all github builds.

Author: vmedea

.github/workflows/build-nightly.yaml

@@ -21,7 +21,7 @@ jobs:
             arch: arm64
     name: Linux
     runs-on: ${{ matrix.os }}
-    container: ghcr.io/scp-fs2open/linux_build:sha-1ff82e8
+    container: ghcr.io/scp-fs2open/linux_build:sha-71099c9
     steps:
       - uses: actions/checkout@v1
         name: Checkout

.github/workflows/build-release.yaml

@@ -50,7 +50,7 @@ jobs:
     name: Linux
     needs: create_release   # Don't run this job until create_release is done and successful
     runs-on: ${{ matrix.os }}
-    container: ghcr.io/scp-fs2open/linux_build:sha-1ff82e8
+    container: ghcr.io/scp-fs2open/linux_build:sha-71099c9
     steps:
       - uses: actions/checkout@v1
         # checks-out your repository under $GITHUB_WORKSPACE, so your workflow can access it.

.github/workflows/build-test.yaml

@@ -15,7 +15,7 @@ jobs:
         configuration: [FastDebug, Release]
     name: Linux
     runs-on: ubuntu-latest
-    container: ghcr.io/scp-fs2open/linux_build:sha-1ff82e8
+    container: ghcr.io/scp-fs2open/linux_build:sha-71099c9
     steps:
       - uses: actions/checkout@v1
         name: Checkout

.github/workflows/cache-master.yaml

@@ -25,7 +25,7 @@ jobs:
             cmake_options: -DFSO_BUILD_WITH_OPENGL=OFF -DFSO_BUILD_WITH_VULKAN=OFF
     name: Linux
     runs-on: ubuntu-latest
-    container: ghcr.io/scp-fs2open/linux_build:sha-1ff82e8
+    container: ghcr.io/scp-fs2open/linux_build:sha-71099c9
     steps:
       - uses: actions/checkout@v1
         name: Checkout

.github/workflows/test-pull_request.yaml

@@ -22,7 +22,7 @@ jobs:
             cmake_options: -DFSO_BUILD_WITH_OPENGL=OFF -DFSO_BUILD_WITH_VULKAN=OFF
     name: Linux
     runs-on: ubuntu-latest
-    container: ghcr.io/scp-fs2open/linux_build:sha-1ff82e8
+    container: ghcr.io/scp-fs2open/linux_build:sha-71099c9
     steps:
       - uses: actions/checkout@v1
         name: Checkout

.github/workflows/weekly-coverity-scan.yaml

@@ -20,7 +20,7 @@ jobs:
     name: Build FSO With Coverity Wrapper
     if: github.repository == 'scp-fs2open/fs2open.github.com'
     runs-on: ${{ matrix.config.os }}
-    container: ghcr.io/scp-fs2open/linux_build:sha-1ff82e8
+    container: ghcr.io/scp-fs2open/linux_build:sha-71099c9
     strategy:
       fail-fast: false
       matrix: