Use `needs` instructions in gitlab.ci

.gitlab-ci/clang10-mpi-release.yml

 build:clang10-mpi-release:
   image: localhost:5000/ubuntu_clang10_mpi
   stage: build
+  needs: []
   script:
     - mkdir -p build/clang10-release-mpi
     - cd build/clang10-release-mpi
@@ -15,8 +16,7 @@ build:clang10-mpi-release:
 test:clang10-mpi-release:
   image: localhost:5000/ubuntu_clang10_mpi
   stage: test
-  dependencies:
-    - build:clang10-mpi-release
+  needs: ["build:clang10-mpi-release"]
   script:
     - mkdir -p build/clang10-release-mpi
     - cd build/clang10-release-mpi

.gitlab-ci/clang10-seq-release.yml

 build:clang10-seq-release:
   image: localhost:5000/ubuntu_clang10
   stage: build
+  needs: []
   script:
     - mkdir -p build/clang10-release-seq
     - cd build/clang10-release-seq
@@ -15,8 +16,7 @@ build:clang10-seq-release:
 test:clang10-seq-release:
   image: localhost:5000/ubuntu_clang10
   stage: test
-  dependencies:
-    - build:clang10-seq-release
+  needs: ["build:clang10-seq-release"]
   script:
     - mkdir -p build/clang10-release-seq
     - cd build/clang10-release-seq

.gitlab-ci/gcc10-seq-release.yml

-build:clang10-seq-release:
-  image: localhost:5000/ubuntu_clang10
+build:gcc10-seq-release:
+  image: localhost:5000/ubuntu_gcc10
   stage: build
+  needs: []
   script:
-    - mkdir -p build/clang10-release-seq
-    - cd build/clang10-release-seq
-    - CXX=clang++-10 CC=clang-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release -DCLANG_FORMAT=/usr/bin/clang-format-10
+    - mkdir -p build/gcc10-release-seq
+    - cd build/gcc10-release-seq
+    - CXX=g++-10 CC=gcc-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release
     - make pugs
   cache:
-    key: "${CI_COMMIT_REF_SLUG}-clang10-release-seq"
+    key: "${CI_COMMIT_REF_SLUG}-gcc10-release-seq"
     paths:
-      - build/clang10-release-seq
+      - build/gcc10-release-seq
     untracked: true
 
-test:clang10-seq-release:
-  image: localhost:5000/ubuntu_clang10
+test:gcc10-seq-release:
+  image: localhost:5000/ubuntu_gcc10
   stage: test
-  dependencies:
-    - build:clang10-seq-release
+  needs: ["build:gcc10-seq-release"]
   script:
-    - mkdir -p build/clang10-release-seq
-    - cd build/clang10-release-seq
-    - CXX=clang++-10 CC=clang-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release -DCLANG_FORMAT=/usr/bin/clang-format-10
+    - mkdir -p build/gcc10-release-seq
+    - cd build/gcc10-release-seq
+    - CXX=g++-10 CC=gcc-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release
     - make run_unit_tests
   cache:
-    key: "${CI_COMMIT_REF_SLUG}-clang10-release-seq"
+    key: "${CI_COMMIT_REF_SLUG}-gcc10-release-seq"
     paths:
-      - build/clang10-release-seq
+      - build/gcc10-release-seq
     untracked: true

.gitlab-ci/gcc8-seq-dbg.yml

 build:gcc8-seq-dbg:
   image: localhost:5000/ubuntu_gcc8
   stage: build
+  needs: []
   script:
     - mkdir -p build/gcc8-seq-dbg
     - cd build/gcc8-seq-dbg
@@ -15,8 +16,7 @@ build:gcc8-seq-dbg:
 test:gcc8-seq-dbg:
   image: localhost:5000/ubuntu_gcc8
   stage: test
-  dependencies:
-    - build:gcc8-seq-dbg
+  needs: ["build:gcc8-seq-dbg"]
   script:
     - mkdir -p build/gcc8-seq-dbg
     - cd build/gcc8-seq-dbg

.gitlab-ci/gcc8-seq-release.yml

 build:gcc8-seq-release:
   image: localhost:5000/ubuntu_gcc8
   stage: build
+  needs: []
   script:
     - mkdir -p build/gcc8-seq-release
     - cd build/gcc8-seq-release
@@ -15,8 +16,7 @@ build:gcc8-seq-release:
 test:gcc8-seq-release:
   image: localhost:5000/ubuntu_gcc8
   stage: test
-  dependencies:
-    - build:gcc8-seq-release
+  needs: ["build:gcc8-seq-release"]
   script:
     - mkdir -p build/gcc8-seq-release
     - cd build/gcc8-seq-release