CI: Update from Julia 1.4 to 1.5.

.appveyor.yml

@@ -1,6 +1,6 @@
 environment:
   matrix:
-  - julia_version: 1.4
+  - julia_version: 1.5
   # - julia_version: latest
 
 platform:

.github/workflows/docs.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        julia-version: [1.4]
+        julia-version: [1.5]
         julia-arch: [x86]
         os: [ubuntu-latest]
     steps:

.travis.yml

@@ -5,7 +5,6 @@ os:
   - osx
 julia:
   - 1.0
-  - 1.4
   - 1.5
   - nightly
 branches:
@@ -13,14 +12,14 @@ branches:
     - master
     - /^v\d+\.\d+(\.\d+)?(-\S*)?$/
 after_success:
-  - if [[ $TRAVIS_JULIA_VERSION = 1.4 ]] && [[ $TRAVIS_OS_NAME = linux ]]; then
+  - if [[ $TRAVIS_JULIA_VERSION = 1.5 ]] && [[ $TRAVIS_OS_NAME = linux ]]; then
       julia --project=test/coverage -e 'using Pkg; Pkg.instantiate();
           using Coverage; Codecov.submit(Codecov.process_folder())';
     fi
 # jobs:
 #   include:
 #     - stage: Documentation
-#       julia: 1.4
+#       julia: 1.5
 #       os: linux
 #       script:
 #         - julia --project=docs -e 'using Pkg; Pkg.instantiate()'