Pull request: all: update go and backend tools

Closes #2576.
Updates #2275.
Updates #2419.
Updates #2443.

Squashed commit of the following:

commit b1a4809ada298d675de12740051ba26fb9945957
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri May 21 14:01:40 2021 +0300

    all: add --local-frontend, upd docker

commit 619ee7c82f27e3405753003dbec556ffb056d025
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu May 20 15:02:33 2021 +0300

    bamboo-specs: bump docker version

commit 5c2b2fbce80afdcc81fd0cb83674dc3d64facbf1
Merge: 6536b32d 9c60aef6
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu May 20 15:01:47 2021 +0300

    Merge branch 'master' into 2275-upd-go

commit 6536b32dd4580425f7dedde6765463a79b9bd699
Merge: 9bb32bc4 6f7fd33a
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed May 19 20:38:48 2021 +0300

    Merge branch 'master' into 2275-upd-go

commit 9bb32bc4c0ac0f3a97195adc75359e48c9c58897
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed May 19 18:48:50 2021 +0300

    all: fix build, imp err handling

commit 6868eac7f7d2980fb706881f53e72afe5f7c3447
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed May 19 18:09:32 2021 +0300

    all: fix github lint

commit ebbb9c55f32fbd57e34e8b161016aa6b291c097c
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed May 19 17:36:56 2021 +0300

    all: update go and backend tools

.github/workflows/build.yml

@@ -1,7 +1,7 @@
 'name': 'build'
 
 'env':
-  'GO_VERSION': '1.15'
+  'GO_VERSION': '1.16'
   'NODE_VERSION': '14'
 
 'on':
@@ -62,6 +62,7 @@
       'with':
         'token': '${{ secrets.CODECOV_TOKEN }}'
         'file': './coverage.txt'
+
   'build-release':
     'runs-on': 'ubuntu-latest'
     'needs': 'test'

.github/workflows/lint.yml

@@ -1,4 +1,8 @@
 'name': 'lint'
+
+'env':
+  'GO_VERSION': '1.16'
+
 'on':
   'push':
     'tags':
@@ -6,14 +10,20 @@
     'branches':
     - '*'
   'pull_request':
+
 'jobs':
   'go-lint':
     'runs-on': 'ubuntu-latest'
     'steps':
     - 'uses': 'actions/checkout@v2'
+    - 'name': 'Set up Go'
+      'uses': 'actions/setup-go@v2'
+      'with':
+        'go-version': '${{ env.GO_VERSION }}'
     - 'name': 'run-lint'
       'run': >
         make go-deps go-tools go-lint
+
   'eslint':
     'runs-on': 'ubuntu-latest'
     'steps':
@@ -22,6 +32,7 @@
       'run': 'npm --prefix="./client" ci'
     - 'name': 'Run ESLint'
       'run': 'npm --prefix="./client" run lint'
+
   'notify':
     'needs':
     - 'go-lint'